Dorsal Tegmental Nucleus


NPR-C immunoreactivity was detected in several regions, including the periaqueductal gray, oculomotor nucleus, red nucleus and trochlear nucleus of the midbrain; the pontine nucleus, dorsal tegmental nucleus, vestibular nucleus, locus coeruleus, trigeminal motor nucleus, nucleus of the trapezoid body, abducens nucleus and facial nucleus of the pons; and the dorsal motor nucleus of the vagus, hypoglossal nucleus, lateral reticular nucleus, nucleus ambiguus and inferior olivary nucleus of the medulla oblongata. Interestingly, NPR-C immunoreactivity was detected in the cholinergic neurons of the oculomotor nucleus, trochlear nucleus, dorsal tegmental nucleus, motor trigeminal nucleus, facial nucleus, dorsal motor nucleus of the vagus, nucleus ambiguus and hypoglossal nucleus.  

Specifically, it has been suggested that the critical HD cell network resides in a reciprocal loop formed by the interconnected lateral mammillary nucleus and dorsal tegmental nucleus of Gudden.  

A subcortical pathway that may convey this information includes the dorsal tegmental nucleus of Gudden (DTN) and the lateral mammillary nucleus (LMN).  

Sole expression of CRF and CRF-BP was apparent in the olfactory bulbs and superior raphe nucleus, respectively, whereas only UI was observed in the corpus mamillare, nucleus of the medial longitudinal fascicle, dorsal tegmental nucleus, nucleus lateralis valvulae, and nucleus interpeduncularis.  

Although HD cells are found in several areas, the principal circuit for generating this signal originates in the dorsal tegmental nucleus and projects serially, with some reciprocal connections, to the lateral mammillary nucleus --> anterodorsal thalamus --> PoS, and terminates in the entorhinal cortex.  

Our results indicate that the SG receives direct inputs from the medial vestibular nucleus and projects to elements of the HD cell-related circuitry, providing a massive input to the contralateral dorsal tegmental nucleus and a moderately dense projection to the shell region of the lateral mammillary nucleus.  

Experiments were designed to determine whether 2 regions of the head direction cell circuit, the anterodorsal thalamic nucleus (ADN) and the dorsal tegmental nucleus (DTN), contribute to navigation.  

The distribution of on- and off-cells in the mesopontine tegmentum overlapped and included the cholinergic PPTg and lateral dorsal tegmental nucleus identified by NADPH diaphorase staining, as well as the cuneiform nucleus and periaqueductal gray.  

These output regions include the dorsal tegmental nucleus, which is part of a navigation-related system that provides a signal for directional heading.  

Robust infection of the dorsal tegmental nucleus (DTN) and nucleus prepositus hypoglossi (PH) in these cases, but not in controls, at both survival intervals identified these nuclei as potential relays of vestibular input to the LMN.  

Recent experimental evidence, however, indicates that HD signal in rodents originates in a reciprocal loop between the lateral mammillary nucleus (LMN) and the dorsal tegmental nucleus (DTN), which is characterized by a paucity of local excitatory axonal collaterals.  

Other labeled structures included the superior lateral parabrachial nucleus, the facial, hypoglossal and trigeminal motor nuclei, the nucleus incertus, the dorsal tegmental nucleus, the dorsal raphe nucleus, the nucleus of the trapezoid body, and the superficial layers of the dorsal horn of the spinal cord.  

The following major afferent nuclei to Vd/Vv were identified: medial and posterior pallial zones of dorsal telencephalic area, and the subpallial supracommissural and postcommissural nuclei of the ventral telencephalic area, the olfactory bulb, dorsal entopeduncular, anterior and posterior parvocellular preoptic and suprachiasmatic nuclei, anterior, dorsal and central posterior dorsal thalamic, as well as rostrolateral nuclei, periventricular nucleus of the posterior tuberculum, posterior tuberal nucleus, various tuberal hypothalamic nuclei, dorsal tegmental nucleus, superior reticular nucleus, locus coeruleus, and superior raphe nucleus.  

Relative to surgery (n=6) and blood pressure control groups (n=6), chemical disinhibition of the dPAG (n=10) induced a significant increase in FLI in the lateral dorsal tegmental nucleus (LDTg) but not the pedunculopontine tegmental nucleus.  

The number of HD and angular head velocity cells was estimated for several brain areas involved in the generation of the HD signal, including the postsubiculum, anterior dorsal thalamus, lateral mammillary nuclei and dorsal tegmental nucleus.  

All these injections gave rise to retrograde labeling in the nucleus incertus but not in the dorsal tegmental nucleus.  

In the mesencephalon, immunoreactive cell bodies were observed in the periaqueductal grey, the dorsal raphe nucleus, the central and pericentral nuclei of the inferior colliculus and the pericentral division of the dorsal tegmental nucleus. In the pons, immunoreactive cell bodies were observed in the dorsolateral division of the pontine nucleus; below the central division of the dorsal tegmental nucleus; above the dorsolateral division of the pontine nucleus, and close to the superior cerebellar peduncle.  

The distribution of R3 relaxin mRNA in adult rat brain was determined and highly abundant expression was only detected in neurons of the ventromedial dorsal tegmental nucleus (vmDTg) in the pons, whereas all other brain areas were unlabelled or contained much lower mRNA levels.  

Efferent targets of the corpus cerebelli are the posterior parvocellular preoptic nucleus, the ventromedial and ventrolateral thalamic nucleus, dorsal posterior thalamic nucleus, periventricular nucleus of posterior tuberculum, dorsal periventricular pretectal nucleus, inferior lobe, optic tectum, torus semicircularis, nucleus of the medial longitudinal fascicle, nucleus ruber, dorsal tegmental nucleus, nucleus lateralis valvulae, reticular formation, torus longitudinalis, and the medial and lateral lobe of the valvula cerebelli.  

These data, together with the localization of transcripts in the pars ventromedialis of the dorsal tegmental nucleus of C57BLK6J mouse brain by in situ hybridization histochemistry, suggest a new role for relaxin in neuropeptide signaling processes.  

The nucleus incertus (NI) is a distinct cell group in caudoventral regions of the pontine periventricular gray, adjacent to the ventromedial border of the caudal dorsal tegmental nucleus.  

One hypothesis of how this representation is generated and updated is via subcortical projections from the dorsal tegmental nucleus (DTN).  

Recent data suggest that the dorsal tegmental nucleus (DTN) may play a critical role in helping to generate the HD cell signal.  

Immunohistochemistry indicates that one or both of the receptor subtypes are expressed in the dorsal raphe, the lateral dorsal tegmental (LDT), the pedunculo pontine (PPT), the locus coeruleus (LC), the locus subcoeruleus, pontis oralis, Barrington's, the trigeminal complex (mesencephalic trigeminal and motor nucleus of the trigeminal nerve), the dorsal tegmental nucleus of Gudden (DTG), the ventral cochlear nucleus (VCA), trapezoid nucleus (TZ), pontine raphe nucleus and the pontine reticular formation.  

The isthmus contained several cholinergic populations: the nucleus isthmi, the lateral nucleus of the valvula, the secondary visceral nucleus, and the dorsal tegmental nucleus.  

Injections of biotinylated dextran were made into different nuclei of the brainstem (i.e., midbrain reticular nucleus, pontine reticular nucleus, deep layers of superior colliculus, periaqueductal grey matter [ ventrolateral, dorsolateral, and lateral columns], pedunculopontine tegmental nucleus, parabrachial nucleus, lateral dorsal tegmental nucleus, substantia nigra [ pars reticulata], locus coeruleus, and dorsal raphe) of Sprague-Dawley rats using stereotaxic coordinates.  

Topographically, the dorsal tegmental nucleus and the laterodorsal tegmental nucleus appeared to be closely associated with 5-HT-ir cells in the caudal DRN.  

Binding of both radioligands was highly correlated, with highest densities in the dorsal tegmental nucleus of the pons, colliculi and hippocampus.  

No hemispheric differences were observed in the lateral dorsal tegmental nucleus.  

Injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) into the medial mammillary nucleus resulted in retrogradely labelled neurons in the ventral tegmental nucleus of Gudden, whereas injections into the lateral mammillary nucleus resulted in large numbers of retrogradely labelled neurons in the ipsilateral dorsal tegmental nucleus of Gudden and in the laterodorsal tegmental nucleus. In the ventral subnucleus of the dorsal tegmental nucleus, moderate to small numbers of retrogradely labelled neurons were also GABA-immunoreactive and approximately ten to 14 WGA-HRP labelled neurons per section were immunoreactive for leu-enkephalin. The ventral subnucleus of the dorsal tegmental nucleus also contained small numbers of retrogradely labelled neurons that displayed either glutamate or substance P-like immunoreactivity. In addition, moderate to small numbers of WGA-HRP-labelled neurons (five to 20 per section) in the laterodorsal tegmental nucleus were immunoreactive for choline acetyltransferase.  

The highest density of immunoreactive fibres was found in the lateral and medial parabrachial nuclei and in the locus coeruleus; a moderate density was observed in the periaqueductal gray and the central reticular nucleus, and a low density was observed in the interpeduncular nucleus, the nucleus incertus, the raphe pallidus nucleus, the paralemniscal reticular nucleus, the laterodorsal tegmental nucleus, the pericentral division of the dorsal tegmental nucleus and the lateral reticular nucleus. Immunoreactive neurons were observed in the superior central nucleus, the pericentral division of the dorsal tegmental nucleus, the interpeduncular nucleus, the nucleus incertus and the dorsal raphe nucleus.  

PKN mRNA was also highly expressed in dopaminergic neurons such as the ventral tegmental area and substantia nigra pars compacta, in serotonergic raphe neurons, and in cholinergic neurons such as nucleus diagonal band, nucleus basalis, and lateral dorsal tegmental nucleus.  

The torus lateralis receives additional afferents from the secondary general visceral nucleus and, sparsely, from the dorsal tegmental nucleus.  

RESP18 mRNA was expressed in POMC cells of the arcuate nucleus, in neuropeptide Y cells of the dorsal tegmental nucleus, lateral reticular nucleus, and hippocampus, and in brainstem catecholaminergic neurons.  

Whether the dorsal tegmental nucleus, caudal to the supratrochlear nucleus, severely affected in all our PEP cases, has a role in vertical gaze needs to be further studied..  

A low density was found in the superior and inferior colliculi, the interpeduncular nucleus, the nucleus sagulum, the superior central nucleus, the cuneiform nucleus, the accessory dorsal tegmental nucleus, the nucleus of the solitary tract, the dorsal motor nucleus of the vagus, and the paralemniscal, magnocellular, gigantocellular, and lateral tegmental fields.  

37 complete frontal and horizontal series of rat brain were studied to compare the distribution of choline acetyltransferase- (ChAT), tyrosine hydroxylase- (TH), substance P- (SP), calbindin D- (Calb) and NADPH-diaphorase (NADPH-d)-positive cells within the cytoarchitectonic borders of the latero-dorsal tegmental nucleus (L-D) and its neighbourhood.  

There were, however, a number of regions reportedly endowed with neurotensin binding sites, including the central amygdaloid nucleus, periaqueductal gray, outer layer of the superior colliculus and dorsal tegmental nucleus, which showed no or divergent patterns of immunostaining, suggesting that they might be expressing a molecularly distinct form of the receptor.  

In agreement with previous binding studies, we observed NK-3 mRNA in the cortex, the amygdala, the hippocampus, the medial habenula, the zona incerta, the paraventricular and supraoptic nuclei of the hypothalamus, the substantia nigra, the ventral tegmental area, the interpeduncular nucleus, the raphe nuclei, the dorsal tegmental nucleus, and the nucleus of the solitary tract.  

These studies revealed highest density of binding sites in cerebellum, anterior olfactory nucleus, islands of Calleja and substantia nigra with appreciable binding site densities in inferior colliculus, superior colliculus, olfactory tubercle and dorsal tegmental nucleus.  

Binding levels are heavy in the nucleus of the solitary tract, medial vestibular nucleus, posterior dorsal tegmental nucleus, area postrema, and caudal spinal trigeminal nucleus by 30 days postnatal.  

In the dorsal tegmental nucleus, GABA enhancement of FNZP binding was enhanced after chronic treatment and this was accompanied by reductions in SR 95531 binding.  

Unilateral electrolytic lesion of thalamic reticular nucleus elicited metabolic depression in the ipsilateral thalamic mediodorsal, centrolateral, ventrolateral and ventromedial nuclei, and metabolic activation in the dorsal tegmental nucleus bilaterally.  

Neurons in the laterodorsal tegmental nucleus (LDTg), ventrolateral dorsal tegmental nucleus (LDTgV), pedunculopontine tegmental nucleus (PPTg), lateral and medial parabrachial nuclei (LPB and MPB) were immunoreactive to brain nitric oxide synthase (NOS) or isoform I.  

This area corresponds to the latero-dorsal tegmental nucleus, which contains cholinergic neurons that have been implicated in the generation of rapid eye movement sleep. In turn, the laterodorsal tegmental nucleus is reciprocally connected with the nucleus pontis oralis in the rostrodorsal pontine reticular formation, which is an area that is involved in the initiation of the physiological patterns of activity that define the state of rapid eye movement sleep.  

The first group was where a significant number of Fos-positive cells were seen 3 h and 24 h after cold exposure, but not observed 14 days after exposure; the regions included the lateral septal nucleus (LS), parvocellular paraventricular hypothalamic nucleus (pPVN), posterior hypothalamic area (PH), supramammillary nucleus (SuM), locus coeruleus (LC), dorsal tegmental nucleus (DTg), vestibular nucleus (Ves), and nucleus of solitary tract (Sol).  

20 complete series of the rat brain, stained with cresylviolet or with the NADPH-diaphorase positive neurons demonstration method were used to compare the topographical organization of the borders of the dorsal mesopontine tegmental nuclei (latero-dorsal tegmental nucleus, dorsal and ventral tegmental nuclei of Gudden, dorsal raphe nucleus and substantia grisea centralis pontis) and to describe in detail NADPH-d positive cells and fibres in this area. We have found that topography of the cells and the borders of the nuclei were similar by the both methods, but NADPH-d histochemistry has shown the extension of NADPH-d positive cells to neighbouring structures and we would divide some nuclei into independent parts (e.g., pars medialis, ventralis and rostralis of the laterodorsal tegmental nucleus).  

When rats were exposed to cold ambient, significant number of Fos-positive neurons was found in the lateral septal nucleus (LS), preoptic hypothalamic area (POA), parvocellular paraventricular hypothalamic nucleus (pPVN), lateral preoptic area (LPO), zona incerta (ZI), paraventricular thalamic nucleus (PV), ventromedial hypothalamic nucleus (VMH), subparafascicular thalamic nucleus (SPF), posterior hypothalamic area (PH), supramammillary nucleus (SuM), microcellular tegmental nucleus (MiTg), lateral lemniscus nucleus (LL), lateral dorsal central grey (CGLD), lateral ventral central grey (CGLV), dorsal parabrachial nucleus (DPB), locus coeruleus (LC), dorsal tegmental nucleus (DTg), vestibular nucleus (Ves), nucleus of solitary tract (Sol), spinal cord, and cerebellum.  

Labeled brainstem populations included the torus semicircularis, ventral tegmental area, superior raphe, parvocellular and ventral isthmal nuclei, and the lateral dorsal tegmental nucleus.  

The signals were especially concentrated in several brain regions such as the olfactory tubercle, accumbens nucleus, caudate putamen, fundus striati, dentate gyrus of the hippocampus, pontine nuclei and dorsal tegmental nucleus.  

Conversely, the hilus of the dentate gyrus, anterodorsal thalamic nucleus, central nucleus of the inferior colliculus, and dorsal tegmental nucleus showed intense to moderate SPR-LI but contained few axons with SP-LI.  

Instead of an input from the valvula cerebelli, the TL and the cerebellum both receive a collateral mossy fiber input from the same source (nucleus lateralis valvulae, dorsal tegmental nucleus).  

A moderate density of immunoreactive fibers was observed in the periaqueductal gray, locus coeruleus, marginal nucleus of the brachium conjunctivum and below the facial nucleus, whereas a low density of such fibers was found in the nucleus of the brachium of the inferior colliculus, pericentral nucleus of the inferior colliculus, nucleus incertus, medial division of the dorsal nucleus of the raphe, accessory dorsal tegmental nucleus, Kölliker-Fuse nucleus, lateral tegmental field, postpyramidal nucleus of the raphe, pericentral division of the dorsal tegmental nucleus, infratrigeminal nucleus, medial nucleus of the solitary tract, spinal trigeminal tract, dorsal motor nucleus of the vagus, and in the lateral reticular nucleus.  

Microinjection of CRF into the medial and lateral parabrachial nucleus, postero-dorsal tegmental nucleus, dorsomedial tegmental area and the ventral part of the nucleus subcoeruleus did not influence colonic transit.  

Indeed, CY 208-243 increased Fos-like immunoreactivity in choline-acetyltransferase-positive neurons in the basal forebrain and lateral dorsal tegmental nucleus.  

All three of the cerebellar nuclei receive 5HT afferents from the nucleus locus coeruleus, the dorsal raphe nucleus, and the dorsal tegmental nucleus.  

The periaqueductal gray, brachium of the inferior colliculus, nucleus of the brachium of the inferior colliculus, locus coeruleus, nucleus incertus, Kölliker-Fuse nucleus, facial nucleus, medial nucleus of the solitary tract and the area postrema contained a moderate density of immunoreactive fibres, whereas the pericentral nucleus of the inferior colliculus, nucleus sagulum, cuneiform nucleus, dorsal nucleus of the raphe, superior central nucleus, central, lateral and paralemniscal tegmental fields, ventral nucleus of the lateral lemniscus, dorsal tegmental nucleus, postpyramidal nucleus of the raphe, nucleus ambiguus, accessory dorsal tegmental nucleus, dorsal motor nucleus of the vagus and the inferior olive had the lowest density of immunoreactive fibres..  

On the other hand, the hypoinnervation displayed by a few regenerating serotonergic fibers was observed in the periventricular part of the prosencephalon, the ventromedial part of the hypothalamus, the dorsal hippocampus, the neocortex, the superior and inferior colliculi, the cerebellum, the dorsal tegmental nucleus of Gudden, the vestibular nuclei, the gracile nucleus and the cuneate nucleus.  

Demonstrated for the first time in rabbits were projections from the lateral dorsal and the pedunculopontine tegmental nuclei, locus coeruleus, dorsal raphe nucleus, Gudden's dorsal tegmental nucleus, pretectum and reticular thalamic nucleus..  

In contrast, electrolytic lesions of the dorsal tegmental nucleus were found to produce a large decrease in GAD-like immunoreactivity which was restricted to the lateral mammillary nucleus. Control lesions placed caudal to the dorsal tegmental nucleus were without effect.  

A high or moderate density of immunoreactive cell bodies was found in the superior central nucleus, nucleus incertus, dorsal tegmental nucleus, nucleus of the trapezoid body, and in the laminar spinal trigeminal nucleus, whereas a low density of such perikarya was observed in the inferior colliculus, nucleus praepositus hypoglossi, dorsal nucleus of the raphe, nucleus of the brachium of the inferior colliculus, and in the nucleus of the solitary tract.  

By contrast, the interpeduncular nucleus, magnocellular part of the red nucleus, central tegmental field, cuneiform nucleus, dorsal tegmental nucleus, nucleus sagulum and the medial and inferior vestibular nuclei had the lowest density, whereas a moderate density of immunoreactive cell bodies was found in the superior colliculus, medial division of the dorsal nucleus of the raphe, nucleus incertus, locus coeruleus and in the Kölliker-Fuse area. The highest density of immunoreactive fibers was observed in the substantia nigra, periaqueductal gray, marginal nucleus of the brachium conjunctivum, medial vestibular nucleus, medial nucleus of the solitary tract, laminar spinal trigeminal nucleus, inferior colliculus, medial division of the dorsal nucleus of the raphe, locus coeruleus, dorsal tegmental nucleus and in the spinal trigeminal tract.  

Here, we demonstrate that in humans there are abundant galanin-containing fibers in the pedunculopontine tegmental nucleus, the lateral dorsal tegmental nucleus and the oral pontine reticular nucleus.  

The cat superior colliculus (SC) receives a dense cholinergic input from three brainstem nuclei, the pedunculopontine tegmental nucleus, the lateral dorsal tegmental nucleus, and the parabigeminal nucleus (PBG).  

The nucleus ruber, cuneiform nucleus, preolivary nucleus, retrorubral nucleus, paracentral division of the tegmental reticular nucleus, central and lateral tegmental fields, and the pericentral division of the dorsal tegmental nucleus had the lowest density of immunoreactive cell bodies.  

In the diencephalon, immunoreactive cells or fibers were observed in the nucleus prethalamicus and the habenula, within the nucleus at the base of the optic tract and the adjacent dorsal tegmental nucleus, the pretectal nuclei A and B, and the nucleus electrosensorius.  

Injections into the lateral mammillary nucleus revealed inputs from the presubiculum, parasubiculum, septal region, dorsal tegmental nucleus, dorsal raphe nucleus, and periaqueductal gray.  

In order to verify the existence of the ventral and posterodorsal tegmental nuclei and to extend previous findings regarding the dorsal tegmental nucleus in the human brainstem, studies were conducted using cyto- and chemoarchitectonics, and computer reconstruction techniques. The dorsal tegmental nucleus featured a cell-poor pericentral part, strongly positive for acetylcholinesterase, and a central part comprised of densely packed small neurons that displayed moderate acetylcholinesterase reactivity and strong substance P-like immunoreactivity. The posterodorsal tegmental nucleus, located in the same transverse plane as the rostral part of the motor nucleus of the trigeminal nerve, was composed of diffusely arranged small to medium neurons with its neuropil displaying moderate acetylcholinesterase reactivity and strong substance P-like immunoreactivity.  

A high density of immunoreactive perikarya was observed in the lateral tegmental field and retrorubral nucleus, whereas a moderate density was found in the nucleus incertus, periaqueductal gray and dorsal tegmental nucleus. Finally, scarce immunoreactive fibers were found in the nucleus of the brachium of the inferior colliculus, inferior central nucleus, nucleus incertus, retrorubral nucleus and dorsal tegmental nucleus..  

We examined the synaptic organization of ascending projections from the pars ventralis of the dorsal tegmental nucleus of Gudden (TDV) and the laterodorsal tegmental nucleus to the lateral mammillary nucleus (LM). Following injection of WGA-HRP into the laterodorsal tegmental nucleus, many anterogradely labeled terminals are found in the LM, but no retrogradely labeled cells are present. These results indicate that almost all axosomatic terminals come from the TDV and the laterodorsal tegmental nucleus, which send inhibitory inputs to the lateral mammillary nucleus..  

A moderate density of cell bodies containing the peptide was observed in the ventral nucleus of the lateral lemniscus, accessory dorsal tegmental nucleus, retrofacial nucleus and in the lateral reticular nucleus, whereas a low density of such perikarya was found in the interpeduncular nucleus, nucleus incertus, nucleus sagulum, gigantocellular tegmental field, nucleus of the trapezoid body, nucleus praepositus hypoglosii, lateral and magnocellular tegmental fields, nucleus of the solitary tract, nucleus ambiguous and in the nucleus intercalatus. Moreover, a moderate density of somatostatin-28 (1-12)-immunoreactive processes was found in the dorsal nucleus of the raphe, dorsal tegmental nucleus, accessory dorsal tegmental nucleus, periaqueductal gray and in the marginal nucleus of the brachium conjunctivum.  

The labelling dendrites were found in neighboured structure (periaqueductal gray, laterodorsal tegmental nucleus, dorsal tegmental nucleus, 4th ventricle).  

Neuronal cell bodies within the lateral hypothalamus, pedunculpontine tegmental nucleus, laterodorsal tegmental nucleus, and the paracentral dorsal tegmental nucleus accumulated 125I-aFGF.  

A medium density of ChAT-positive terminals was observed in all or parts of: the substantia nigra zona compacta (ferret), ventral tegmental area (ferret), superficial grey layer of the superior colliculus, intermediate and deep layers of the superior colliculus, lateral central grey, area medial to the parabigeminal nucleus, inferior colliculus, dorsal tegmental nucleus, ventral tegmental nucleus (ferret), pontine nuclei, ventral nucleus of the lateral lemniscus (ferret), midline pontine reticular formation, ventral cochlear nucleus, dorsal cochlear nucleus, lateral superior olive, spinal trigeminal nuclei, prepositus hypoglossal nucleus, lateral reticular nucleus, paragigantocellular nucleus, and the dorsal column nuclei including the cuneate, external cuneate, and gracile nuclei.  

In addition, the dorsal and medial raphe nuclei of the metencephalon, together with the locus coeruleus and the dorsal tegmental nucleus, received lateral septal efferents..  

Cholinergic neurons in the pedunculopontine nucleus (PPN) and lateral dorsal tegmental nucleus (LDT) were labeled using nicotinamide adenosine dinucleotide phosphate (NADPH)-diaphorase histochemistry, while catecholaminergic neurons of the locus ceruleus (LC) were labeled immunocytochemically using an antibody to tyrosine hydroxylase.  

Both the laterodorsal tegmental nucleus and the ventromedial portion of the dorsal tegmental nucleus presented labeled cells.  

alpha BT-sensitive NBT binding sites were found in highest density in the lateral geniculate nucleus, the subthalamic nucleus, the dorsal tegmental nucleus, and the medial mammillary nucleus (lateral part).  

The number of neurons was estimated in the ventral part of the dorsal tegmental nucleus and in the ventral tegmental nucleus of Gudden in brains of male ASH/TO strain mice aged 6, 15, 25, 28 and 31 months.  

Phenylethanolamine N-methyltransferase innervation in the dorsal pons was not restricted to the locus coeruleus but was also prominent in neighboring areas such as Barrington's nucleus and the lateral dorsal tegmental nucleus of Gudden..  

Strongly- or moderately-labeled neurons were found in the cranial nuclei, sensory nuclei such as the spinal trigeminal nucleus, principal trigeminal nucleus, gracile and cuneate nuclei, dorsal and ventral cochlear nuclei, superior olivary nucleus, medial and lateral trapezoid nuclei, lateral lemniscus and vestibular nuclei, red nucleus, parabrachial area, cerebellar nuclei, dorsal tegmental nucleus, reticular formation and parafascicular nucleus.  

Moderate concentrations of converting enzyme also occur in the paraventricular, medial habenula, lateral habenula and central median nuclei of the thalamus, the amygdala, the central gray, the locus coeruleus, the parabrachial nucleus and dorsal tegmental nucleus.  

Injections of WGA-HRP into the medial mamillary nucleus resulted in dense anterograde and retrograde labeling in the ventral tegmental nucleus, while injections in the lateral mamillary nucleus resulted in dense anterograde labeling in the dorsal tegmental nucleus pars dorsalis and dense anterograde and retrograde labeling in the pars ventralis of the dorsal tegmental nucleus.  

In adult mice a large reduction of afferents occurs in the diagonal band of Broca, the posterior thalamic nucleus, the zona incerta, the lateral hypothalamic area, the nuclei of amygdaloid complex, the posterior hypothalamic nucleus, the reticular pontine nucleus, the dorsal and medial raphe nuclei and the dorsal tegmental nucleus.  

The synaptic organization of projections from the lateral mammillary neurons within the dorsal tegmental nucleus of Gudden is studied in the rat with the aid of anterograde transport of horseradish peroxidase conjugated with wheat germ agglutinin (WGA-HRP) and visualized with tetramethylbenzidine. The dorsal tegmental nucleus consists of the pars ventralis (TDV) and the pars dorsalis (TDD). The normal neuropil of the dorsal tegmental nucleus contains three classes of axodendritic terminals, that is, terminals containing round, flat, and pleomorphic vesicles.  

Tectal injections anterogradely labeled various pretectal nuclei bilaterally, as well as ipsilaterally the dorsal preglomerular and dorsal posterior thalamic nuclei, some nuclei in the torus semicircularis, the dorsal tegmental nucleus, nucleus isthmi, and, again bilaterally, the superior reticular formation.  

Type I PPE neurons were observed in diverse brainstem structures including the mesencephalic and pontine central gray matter, various reticular and raphe nuclei, the ventral tegmental area of Tsai, the interpeduncular nucleus, the nucleus of the brachium of the inferior colliculus, the ventral and dorsal tegmental nuclei of Gudden, the sphenoid nucleus, the laterodorsal tegmental nucleus, Barrington's nucleus, the parabrachial region, the lateral lemniscus and its related nuclei, the trapezoid nucleus, the rostral and ventromedial periolivary nuclei, the mesencephalic trigeminal and principal sensory trigeminal nuclei, the locus coeruleus, the subcoeruleus nucleus, the medial and spinal vestibular nuclei, the dorsal and ventral cochlear nuclei, the medial and lateral cerebellar nuclei, the Roller nucleus, and the intermedius nucleus of the medulla. Type II PPE neurons were found in the superior colliculus, the inferior colliculus, the central part of the dorsal tegmental nucleus, and as Golgi neurons in the granular layer of the cerebellum.  

The present study demonstrates that (i) the lateral lemniscus is supplied by fibers of the medullary acoustic nucleus (nucleus intermedius) and the superior olive; (ii) the subtectal dorsal tegmentum can be clearly separated into a dorsally located torus semicircularis and a ventrally situated dorsal tegmental nucleus, the former processing auditory and vibratory, the latter vestibular signals; and (iii) the hearing capabilities of this animal, as estimated from the tuning of toral units, are comparable to those of anurans with extratympanic sound transmission.  

Large neurons were concentrated in the caudal midbrain (pedunculopontine tegmental nuclei), in the oral pontine reticular nucleus and in the lateral dorsal tegmental nucleus.  

However, in the locus coeruleus, dorsal tegmental nucleus and most structures associated with auditory processing, tolerance to the depressant effect of diazepam upon glucose use had occurred suggesting the importance of these structures in the sedative effect of diazepam.  

The central gray showed moderate to high-density labeling throughout its entire rostro-caudal extent, with very high binding in the dorsal tegmental nucleus and the locus coeruleus.  

Projections from the dorsal tegmental nucleus terminated in the ipsilateral lateral mamillary nucleus, whereas afferent projections from the anterior and posterior subnuclei of the ventral tegmental nucleus terminated topographically in the medial mamillary nucleus.  

The lateral mammillary nucleus contains neurons whose collateral fibers project to both the dorsal tegmental nucleus of Gudden and the ipsilateral or contralateral anterodorsal thalamic nucleus, to both the medial pontine nucleus and the anterodorsal thalamic nucleus, and to both the dorsal tegmental nucleus of Gudden and the medial pontine nucleus.  

Based upon retrograde HRP labeling, the principal afferents to the VTN region of the cmPRF originated from the medial and lateral mammillary nuclei, and lateral habenular nucleus, and to a lesser extent from the interpeduncular nucleus, lateral hypothalamus, dorsal tegmental nucleus, superior central nucleus, and contralateral nucleus reticularis pontis caudalis. Some projections were also observed to nucleus reticularis pontis oralis and caudalis, superior central nucleus, and dorsal tegmental nucleus adjacent to the VTN....  

The lateral dorsal tegmental nucleus (LDT) provides ascending cholinergic projections to forebrain structures such as prefrontal cortex, septum, habenula, and thalamus, but relatively little is known of the physiology of LDT neurons.  

Heavily stained NADPH-diaphorase-positive neurons with many prominent cell processes were observed in the cerebral cortex, white matter, caudate nucleus, putamen, nucleus accumbens, septal nucleus, amygdala, anterior, lateral and posterior hypothalamic areas, dorsolateral part of the periaqueductal gray, superior colliculus, central tegmental field (Berman) (pedunculopontine tegmental area), dorsal tegmental nucleus, nucleus coeruleus, mesencephalic and pontine reticular formation, gigantocellular and magnocellular tegmental fields, nucleus facialis, and motor nucleus of the vagus. Intensely stained NADPH-diaphorase-positive nerve fibers were found in the stria terminalis, marginal region of the central tegmental field, dorsal tegmental nucleus, and spinal trigeminal tract as well as around the brachium conjunctivum.  

Additional brain areas showing significant alterations in GU in response to CRF included anteroventral, anterior pretectal, and posterolateral nuclei of the thalamus, fornix, dorsal tegmental nucleus, spinal trigeminal nucleus, and cuneate nucleus.  

The laterodorsal tegmental nucleus (ntdl) contains a cluster of cells located just medial to the locus coeruleus in the pontine brainstem. The dorsal tegmental nucleus, dorsal raphe nucleus, locus coeruleus, and the parabrachial region contained a dense and varied assortment of peptides with distinct positions and patterns.  

The neuron in the pars ventralis of the dorsal tegmental nucleus of Gudden (TDV) is similar to that in the TVP, but its average size is significantly smaller (10.0 x 18.8 microns, 151.4 microns 2), and its organelles are also less well developed. The pars dorsalis of the dorsal tegmental nucleus of Gudden (TDD) is composed of spindle shaped, small neurons (6.9 x 16.2 microns, 85.1 microns 2) characterized by their irregular shaped nucleus with its invaginated envelope.  

Pressure injections of the anterograde tracer wheat germ agglutinin conjugated with horseradish peroxidase (WGA-HRP) into the infralimbic (IL) and prelimbic (PL) regions of the medial frontal cortex of the rat produced anterograde, terminal-like labeling in the lateral dorsal tegmental nucleus (LDTg) of the dorsal pons and the ventral, ventrolateral, intermediate, medial and commissural subnuclei of the nucleus of the solitary nucleus (NTS) in the dorsomedial medulla.  

The periaqueductal gray around the dorsal tegmental nucleus projects bilaterally to the supramammillary nucleus. The pars alpha of the pontine periaqueductal gray projects bilaterally to the peripheral part of the lateral mammillary nucleus, whereas the pars ventralis of the dorsal tegmental nucleus projects ipsilaterally to the lateral mammillary nucleus.  

The mu agonists, injected 15 min before [ 14C]2-DG, decreased LCGU in thalamic nuclei, including some of those which have been implicated in somatosensory processing, and in the dorsal tegmental nucleus.  

Within the pons, neurotensin binding sites were detected in the reticulotegmental nucleus, the pontine nuclei, the dorsal tegmental nucleus, the laterodorsal and pedunculopontine tegmental nuclei and the nuclei raphe dorsalis and medianus.  

Both TGF alpha-I and retrogradely transported FG were found within the same neurons in the interpeduncular nucleus (IPN) after bilateral FG injections in the dorsal tegmental nucleus (DTg).  

Neurons in the hypothalamus (lateral, dorsal, ventromedial, dorsomedial, and supraoptic nuclei), raphe system, dorsal tegmental nucleus, locus ceruleus, Kölliker-Fuse nucleus, dorsal parabrachial region, and central tegmental field were positive.  

Other cholinergic neurons that were also retrogradely labeled with HRP were located in the caudal PPN and in the lateral dorsal tegmental nucleus.  

We studied the afferent source of L-enkephalin-like immunoreactive (L-ENKLI) fibers in the ventral tegmental nucleus (VT) of Gudden, and efferent and afferent connections of L-ENKLI structures in the dorsal part of the dorsal tegmental nucleus (DDT) of Gudden in the rat, using immunocytochemistry combined with knife-cut and lesion experiments.  

The following areas were newly identified as areas rich in CHAT-I fibers: the interpeduncular nucleus, medial geniculate body, central gray matter of pons, pontine nucleus, parabigeminal nucleus, dorsal tegmental nucleus of Gudden, lateral trapezoid nucleus, inferior colliculus, dorsal and ventral cochlear nuclei, medial and lateral vestibular nuclei, reticular formation of medulla oblongata, and gelatinosa of caudal trigeminal spinal tract nucleus.  

In the tegmentum, AChE was localized in the pedunculopontine nucleus (PPN), beginning rostrally at the caudal pole of the substantia nigra and extending caudally to the level of the parabrachial nuclei, and in the lateral dorsal tegmental nucleus (LDTN) of the central gray.  

Bilateral electrolytic lesions of the habenular nuclei decreased LCGU in a limited number of well-defined brain areas (the interpeduncular nucleus, median and dorsal raphe, mammillary body and dorsal tegmental nucleus) at 7 and 14 days after lesions. These changes were also observed 180 days following lesioning except that of the dorsal tegmental nucleus.  

Major areas of cell body staining included the medial habenular nucleus, the ventromedial nucleus of the hypothalamus, the interpeduncular nucleus, the lateral dorsal tegmental nucleus, the nucleus raphe pallidus, and the nucleus of the solitary tract.  

In contrast, nuclei of the septum (diagonal band of Broca, septohippocampal nucleus, dorsal part of the lateral septal nucleus), the rostrodorsal part of the hippocampus and other discrete nuclei [ endopyriform nucleus, anterior cortical amygdaloid nucleus, the vermis columns (9-10), the dorsal tegmental nucleus, the hypoglossal and ambiguus nucleus] had high levels of [ 125I]Bolton and Hunter substance P binding but were only labeled weakly by [ 125I]Bolton and Hunter eledoisin.  

DYN B cell bodies were present in nonpyramidal cells of neo- and allocortices, medium-sized cells of the caudate-putamen, nucleus accumbens, lateral part of the central nucleus of the amygdala, bed nucleus of the stria terminalis, preoptic area, and in sectors of nearly every hypothalamic nucleus and area, medial pretectal area, and nucleus of the optic tract, periaqueductal gray, raphe nuclei, cuneiform nucleus, sagulum, retrorubral nucleus, peripeduncular nucleus, lateral terminal nucleus, pedunculopontine nucleus, mesencephalic trigeminal nucleus, parabigeminal nucleus, dorsal nucleus of the lateral lemniscus, lateral superior olivary nucleus, superior paraolivary nucleus, medial superior olivary nucleus, ventral nucleus of the trapezoid body, lateral dorsal tegmental nucleus, accessory trigeminal nucleus, solitary nucleus, nucleus ambiguus, paratrigeminal nucleus, area postrema, lateral reticular nucleus, and ventrolateral region of the reticular formation.  

Ammon's horn, dentate gyrus, subiculum, pre- and parasubiculum, lateral thalamic nucleus (intergeniculate leaflet), bed nucleus of the stria terminalis, medial preoptic area, lateral hypothalamus, mediobasal hypothalamus, supramammillary nucleus, pericentral and external nuclei of the inferior colliculus, interpeduncular nucleus, periaqueductal central gray, locus coeruleus, dorsal tegmental nucleus of Gudden, lateral superior olive, lateral reticular nucleus, medial longitudinal fasciculus, prepositus hypoglossal nucleus, nucleus of the solitary tract and spinal nucleus of the trigeminal nerve.  

A part of the nucleus incertus, located dorsomedial to the dorsal tegmental nucleus, projects to the contralateral half of the rostral subnucleus of the IPN; the pars caudalis of the dorsal tegmental nucleus projects sparsely to the rostral lateral, dorsal lateral, lateral, caudal, and apical subnuclei predominantly contralaterally; the laterodorsal tegmental nucleus, to most of the subnuclei predominantly contralaterally; the ventromedial central gray rostral to the dorsal tegmental nucleus and lateral to the dorsal raphe nucleus projects to the rostral lateral and dorsal lateral subnuclei predominantly contralaterally; the median raphe nucleus, substantially to all subnuclei; the medial habenular nucleus, in a topographic manner, to the rostral, central, and intermediate subnuclei, to the rostral lateral and lateral subnuclei predominantly ipsilaterally, and to the dorsal lateral subnucleus predominantly contralaterally; the supramammillary nucleus and areas around the origin of the mammillothalamic tract and near the third ventricle project sparsely to the ventral part of the rostral subnucleus and to the central, lateral, caudal and apical subnuclei; the nucleus of the diagonal band, sparsely to the rostral, central, dorsal lateral, caudal, and apical subnuclei.  

Perikarya containing both the black granular retrograde labeling and brown peroxidase-immunoreactivity were found in the nuclei of the solitary tracts, the caudal ventrolateral reticular formation, the lateral dorsal tegmental nucleus and the paraventricular, dorsomedial and lateral hypothalamic nuclei.  

Further but weaker labeling occurred in the medial septal nucleus, diagonal band of Broca, olfactory tubercle, paraventricular, anterior, mediodorsal, and central lateral thalamic nuclei, lateral habenula, ventral tegmental area of Tsai, interpeduncular nucleus, parabrachial, raphe, dorsal tegmental nucleus and the locus caeruleus.  

the dorsal tegmental nucleus of Gudden, the dorsolateral tegmental nucleus and the caudal extension of the dorsal raphe nucleus.  

Among extrahypothalamic regions, the substantia nigra, dorsal tegmental nucleus, cuneiform nucleus, dorsal parabrachial nucleus, spinal tract trigeminal nerve, interior olive, solitary nucleus, and layers I and II of the spinal cord contained 7B2-immunoreactive material.  

Dense binding was observed in the telencephalon (medial prefrontal, insular and outer layers of the temporal cortex, nucleus accumbens, fundus striatum, central and inferior lateral amygdaloid nuclei, most caudal caudate putamen, organum vasculosum laminae terminalis, subfornical organ), the diencephalon (anterior hypothalamic, suprachiasmatic, arcuate, paraventricular, dorsomedial, periventricular, reuniens, rhomboid, lateral thalamic pretectalis and habenula nuclei, zona incerta), in the mesencephalon (superficial layers of the superior colliculus, central nucleus of the geniculate body, inferior colliculus, nucleus of the fifth nerve, locus coeruleus, nucleus of the mesencephalic tract, the dorsal tegmental nucleus, superior olive), in the molecular layer of the cerebellum, in the medulla oblongata (inferior olive, nucleus tractus solitarii, nucleus commissuralis, nuclei of the tenth and twelfth nerves, the prepositus hypoglossal and the gracilis nuclei, dorsomedial part of the spinal trigeminal tract), in the dorsal gray matter of the spinal cord (laminae I-VI) and the confines of the central canal.  

Still other SS-positive perikarya and fibers were associated with the tegmentopeduncular tract and the medial division of the dorsal tegmental nucleus.  

The number of nerve cells was counted and the volume of their nucleolus measured in the nucleus basalis of Meynert, the locus caeruleus, the dorsal motor vagus, the dorsal tegmental nucleus and the substantia nigra of seven patients with Down's syndrome, six of whom were over 50 years of age and showed within their cerebral cortex and hippocampus numerous senile plaques and neurofibrillary tangles. The six middle-aged patients showed significant loss of cells from nucleus basalis, locus caeruleus, dorsal motor vagus and dorsal tegmental nucleus but no loss from substantia nigra; nucleolar volume was, however, reduced in all five cell types.  

substantia nigra pars lateralis, interpeduncular nucleus, inferior colliculus, nucleus cuneiformis, dorsal tegmental nucleus of Gudden, nucleus laterodorsalis tegmenti, nucleus vestibularis medialis, nucleus vestibularis inferioris, in the fasciculus longitudinalis medialis and nucleus parvocellularis compacta.  

Gudden's tegmental nuclei in the rabbit can be divided into a pars principalis of the ventral tegmental nucleus (TVP), a pars ventralis of the dorsal tegmental nucleus (TDV), and a pars dorsalis of the dorsal tegmental nucleus (TDD).  

Neurons containing both HRP and ChAT, which represented cholinergic neurons projecting directly to the thalamus, were found in the midbrain and pons in the lateral tegmental reticular formation, parabrachial region and lateral dorsal tegmental nucleus.  

The areas which had only efferent connections from MP were accumbens, caudate putamen, ventral pallidum, substantia innominata, lateral habenular nucleus, paratenial thalamic nucleus, paraventricular thalamic nucleus, mediodorsal thalamic nucleus, reuniens thalamic nucleus, median eminence, medial mammillary nucleus, subthalamic nucleus, pars compacta of substantia nigra, oculomotor nucleus, red nucleus, laterodorsal tegmental nucleus, reticular tegmental nucleus, cuneiform nucleus, nucleus locus coeruleus, and dorsal motor nucleus of vagus among which substantia innominata and median eminence were previously reported. Efferent connections to the nucleus of Darkschewitsch, interstitial nucleus of Cajal, dorsal tegmental nucleus, ventral tegmental nucleus, vestibular nuclei, nucleus raphe obsculus were very weak or abscent in the ventral approach while they were observed in dorsal approach. Previously reported afferent connections from dorsal tegmental nucleus, cuneiform nucleus, and nucleus locus ceruleus were not detected in this study.(ABSTRACT TRUNCATED AT 400 WORDS).  

WGA-HRP injections into the LD or LP labeled also a considerable number of neurons in the dorsal raphe nucleus and the dorsal tegmental nucleus bilaterally with homolateral predominance, but the nucleus of Darkschewitsch contained labeled neurons only after the LD injection..  

Scant but consistent labeling occurred in the cingular, retrosplenial, and insular cortices, within the medial forebrain bundle, fields of Forel, zona incerta, ventral tegmental area of Tsai, substantia nigra, pretectal area, periaqueductal gray, dorsal tegmental nucleus, locus ceruleus, and raphe complex.  

Of brainstem afferents projecting to IPN, the most intensely labeled neurons were present in a circumscribed region overlying the dorsal aspect of the dorsal tegmental nucleus, an area described in the cat as the nucleus incertus [ 5], and which we now suggest is present in the rat.  

The afferent and efferent connections of the dorsal tegmental nucleus (DTN) were studied in the rat using axoplasmic transport techniques. Based on the differences of connections and cytoarchitecture between the pars centralis and the pars ventromedialis, the pars ventromedialis may be an entity separate from the dorsal tegmental nucleus..  

The number of nerve cells was counted in locus caeruleus, dorsal motor vagus, dorsal tegmental nucleus and substantia nigra and the volume of their nucleolus measured in 30 patients with Alzheimer's disease ranging from 48-92 years of age and in 67 control patients without neurological disease. Less extensive changes were present in the dorsal tegmental nucleus and these were also age dependent in their severity.  

The dorsal tegmental nucleus of Gudden (TD) is composed of the pars dorsalis (TDD) and the pars ventralis ( TDV ) in the cat, rat, guinea pig, and golden hamster, but the TD of the house shrew can not be divided.  

The pars caudalis and pars dorsalis magnocellularis project to the septum, hippocampus and entorhinal cortex; a part of the pars medialis and the pars paramediana, to the dorsal thalamus; all subnuclei, to the midbrain raphe; and the pars lateralis, to the dorsal tegmental nucleus..  

In the pons, anterograde labeling was present in the parabrachial nuclei, the dorsolateral tegmental nucleus, and the pericentral division of the dorsal tegmental nucleus.  

The mammillotegmental tract projected caudally and terminated in the dorsal tegmental nucleus and central gray.  

The dorsal tegmental nucleus of Gudden is situated within the central gray matter. In the green monkey and man, we could not find a ventral tegmental nucleus of Gudden, and in the house shrew and man, the pars ventralis and pars dorsalis of the dorsal tegmental nucleus of Gudden could not be separated..  

The most posterior labeled neurons were found in the locus ceruleus, dorsal tegmental nucleus of Gudden, nucleus annularis, nucleus centralis superior Bechterew, nucleus dorsalis raphae and the most dorsomedial part of the nucleus reticularis tegmenti pontis.  

The retrogradely-filled cells of the brainstem were situated principally in the nucleus tegmenti pedunculopontinus, the locus coeruleus complex, the parabrachial nuclei and the dorsal tegmental nucleus of Gudden; in each case, labelled cells were more numerous on the ipsilateral side.  

Cells accumulating EB after basolateral amygdala infusion but demonstrating no, weak, or moderate AChE activity were seen in the orbitofrontal, anterior cingulate, temporal, and insular cortices; the mediodorsal, paraventricular, and parataenial nuclei of the thalamus; the periventricular gray substance; the ventromedial mesencephalic tegmentum; the lateral and compact portions of the substantia nigra; the dorsal raphe; the dorsal tegmental nucleus; and the dorsal parabrachial nucleus.  

There were a few labeled cells in the accessory dorsal tegmental nucleus, the nucleus raphe dorsalis (RD), the nucleus centralis superior, the nucleus of the locus coeruleus, the gray matter of the floor of the fourth ventricle, and the nucleus of diagonal band of Broca, but there were no obvious patterns in the projections of these nuclei to the different sub-nuclei of the IP complex.  

The lateral mamillary nucleus projects through the mamillothalamic tract bilaterally upon the anterodorsal nuclei of the thalamus, and through the mamillotegmental system to the dorsal tegmental nucleus; it also appears to contribute fibers to the medial forebrain bundle.  

After injections of HRP in the intermediate part of the MD, labeled cells were seen mainly in the interpeduncular nucleus, substantia nigra, dorsal and centralis superior raphe nuclei, dorsal tegmental nucleus, and coeruleus complex. Labeled cells were also observed in the substantia nigra, locus coeruleus, dorsal tegmental nucleus, cuneiform area, and the mesencephalic reticular formation.  

In a light microscopic study we used the wet fluorescent method and counted numbers of fluorescent LC cells and obtained 1326 +/- 64 in oneside, and many processes of LC cells reached and expanded into the latero-dorsal tegmental nucleus and nucl.  

VIP concentrations are moderately high (0.8-1 ng/mg protein) in gracile nucleus, area postrema, nucleus of the solitary tract, motor nucleus of the XIIth, locus ceruleus and dorsal tegmental nucleus.  

Confirmatory data and some details of organization were also obtained for projections to the IPN from other areas, including the medial and dorsal raphe nuclei, the dorsal tegmental nucleus of Gudden, and the adjacent dorsolateral tegmental nucleus.  

The bulk of the neurons of the dorsal tegmental nucleus (Gudden's) are produced between days E13 and E15, whereas most of the neurons of the deep (ventral) tegmental nucleus are produced on day E15.  

In the pontine region, the locus coeruleus, parabrachial nuclei, nucleus of the lateral lemniscus, and the dorsal tegmental nucleus of Gudden all had reactive cells.  

In the pontine region, the locus coeruleus, the parabrachial nuclei and the dorsal tegmental nucleus of the Gudden had cells with reaction products.  

Major projections to the IPN originate in the medial habenular nucleus, the region surrounding the dorsal tegmental nucleus (accessory dorsal tegmental nucleus and the so-called dorsal tegmental nucleus pars lateralis), and the midbrain raphe (nucleus centralis superior and nucleus raphe dorsalis).  

Serotonergic dendrites predominated in these bundles, but non-serotonergic dendrites from cells of the dorsal tegmental nucleus, adjacent reticular formation, and NCS also were present.  

These structures included the ventromedial nucleus of the hypothalamus, the mamillary nuclei, the medial geniculate nuclei, globus pallidus, zona incerta, nucleus ambiguus, supraoptic nucleus, paraventricular nucleus, medial nucleus of the solitary tract, dorsal tegmental nucleus, red nucleus, inferior olivary nucleus, hippocampus and amygdaloid complex.4.  

After injections which involve Ammon's horn, the dentate gyrus, and the subicular complex, retrogradely labeled neurons are found in the following regions: in the amygdala (specifically in the anterior amygdaloid area, the basolateral nucleus, and the periamygdaloid cortex); in the medial septal nucleus and the nucleus of the diagonal band; in the ventral part of the claustrum; in the substantia innominata and the basal nucleus of Meynert; in the rostral thalamus (specifically in the anterior nuclear complex, the laterodorsal nucleus, the paraventricular and parataenial nuclei, the nucleus reuniens, and the nucleus centralis medialis); in the lateral preoptic and lateral hypothalamic areas, and especially in the supramammillary and retromammillary regions; in the ventral tegmental area, the tegmental reticular fields, the raphe nuclei (specifically in nucleus centralis superior and the dorsal raphe nucleus), in the nucleus reticularis tegmenti pontis, the central gray, the dorsal tegmental nucleus, and in the locus coeruleus..  

The following new sources of projections to the laterodorsal thalamic nucleus (LD) were observed: the zona incerta, the lateral dorsal tegmental nucleus (bilaterally), the lateral hypothalamus and the precentral agranular cortex..  

Cell bodies are found in the substantia gelatinosa and interpolaris zones of the trigeminal nuclear complex, the nucleus of the solitary tract, in the vicinity of the nucleus raphé magnus, in the dorsal cochlear, medial vestibular, and paraolivary nuclei and, dorsal to this last region, in the parabrachial nuclei and the dorsal tegmental nucleus of Gudden, in the periaqueductal gray matter and interpeduncular nucleus and along the borders of the lateral lemniscus and medial geniculate.  

The principal observations were that toxin binding sites are predominantly associated with central areas of the brain in direct receipt of sensory inputs (the main and accessory olfactory bulbs, superior colliculus, ventral lateral geniculate nucleus, cochlear nuclei, the substantia gelatinosa of the spinal cord and spinal trigeminal nucleus, the principal sensory nucleus of the trigeminal, and the dorsal column nuclei) and with limbic areas of the brain (hippocampus, amygdala, olfactory tubercle, medial mammillary nucleus, and the dorsal tegmental nucleus of Gudden).  

Analysis of the regional distribution of [ 125I]alpha-Btx binding by autoradiography of frontal brain sections revealed high labeling in the hippocampus, hypothalamic supraoptic, suprachiasmatic and periventricular nuclei, ventral lateral geniculate and the mesencephalic dorsal tegmental nucleus.  

Most of the cells providing ascending fibers to the neocortex were located in the pons (locus coerulus and related structures, central gray substance, dorsal tegmental nucleus, raphe nuclei, reticular nuclei); labeled neurons were also identified in the mesencephalon, mainly in the periaqueductal gray and in the nucleus linearis rostralis.  

With a rating of high in both medial and lateral mammillary nuclei (11 animals) three major projection sites were seen: the dorsal tegmental nucleus (DTN), the ventral tegmental nucleus (VTN) and a pontine region which included both the pontine grey and the tegmental reticular nucleus.  

Active areas consisted of three regions: 1) lateral inhibitory: Locus subcoeruleus and anteroventral locus coeruleus (mean deltaACTH: -189, -164, -145 pg/ml at 1.5,3.0 and 6.0 min respectively, P less than 0.01);2) intermediate facilitatory:principal locus coeruleus and lateral ventral tegmental nucleus (mean deltaACTH: +81, +68, +37 pg/ml; P less than 0.05); and 3) medial inhibitory: dorsal tegmental nucleus, dorsal raphé and medial ventral tegmental nucleus (mean deltaACTH; -211, -212, -115 pg/ml; P less than 0.01).  

Short latency responses accompanied by evoked field potentials were recorded also after stimulation of dorsal tegmental nucleus.  

Terminal degeneration was seen in the interpeduncular nucleus primarily in the dorsal and posterior parts, in the ventral tegmental nucleus and throughout the central gray, but was more densely clustered in the region of the dorsal tegmental nucleus..  


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