Oral Pontine Reticular Nucleus


The ventral part of the oral pontine reticular nucleus (vRPO) is involved in the generation and maintenance of rapid eye movement (REM) sleep.  

A wide band of retrogradely labeled cells was found in the gigantocellular reticular nucleus (Gi) and labeled cells continued rostrally into the caudal pontine reticular nucleus (PnC) and into the oral pontine reticular nucleus (PnO).  

Here, we report the effects on sleep-wakefulness produced by low-volume microinjections of hypocretin (Hcrt)1 (20-30 nL, 100, 500 and 1000 microm) and carbachol (20-30 nL, 0.1 m) delivered in two areas of the oral pontine tegmentum of free-moving cats with electrodes for chronic sleep recordings: in the dorsal oral pontine tegmentum (DOPT) and in the ventral part of the oral pontine reticular nucleus (vRPO).  

The ventral part of the oral pontine reticular nucleus (vRPO) is a demonstrated site of brainstem REM-sleep generation and maintenance.  

From a multidisciplinary study in our laboratory we have compiled numerous findings on the role played by the inhibitory neurotransmitter GABA in the ventral part of the oral pontine reticular nucleus (vRPO), REM sleep induction and maintenance brainstem structure.  

Reinoso s group found out that the paramedian ventral area of the oral pontine reticular nucleus is the conductor in the establishment of REM sleep..  

The aim of the present study was to examine the effect of the PeF area and hypocretin on the electrophysiological activity of neurons of the oral pontine reticular nucleus (PnO), which is an important structure in the generation and maintenance of rapid eye movement sleep.  

GABA mediates inhibitory effects in neurons of the ventral part of the oral pontine reticular nucleus (vRPO).  

The ventral part of the cat oral pontine reticular nucleus (vRPO) is the site in which microinjections of small dose and volume of cholinergic agonists produce long-lasting rapid eye movement sleep with short latency.  

The posterior lateral hypothalamus (PLH) has long been considered crucial to normal wakefulness while the ventral part of the oral pontine reticular nucleus (vRPO) is involved in the generation and maintenance of rapid eye movement (REM) sleep.  

Studies in the authors>> laboratory, mapping the pontine tegmentum with small volume carbachol (a cholinergic agonist) microinjections, have demonstrated that the executive neurons for REM sleep generation are neither located in the dorsal part of the pontine tegmentum, nor diffusely spread through the medial pontine reticular formation: they are concentrated in a discrete area in the ventral part of the oral pontine reticular nucleus (vRPO).  

The ventral part of the oral pontine reticular nucleus (vRPO) is an important region for the generation and maintenance of REM sleep.  

To elucidate a functional involvement of amino acids in the regulation of vigilance states, we investigated time-course changes of glycine (Gly), glutamate (Glu), and glutamine (Gln) in the extracellular fluid of the oral pontine reticular nucleus (PnO) in freely behaving rats by an in vivo microdialysis technique.  

Cholinergic and PACAPergic systems within the oral pontine reticular nucleus (PnO) play a critical role in REM sleep generation in rats.  

In an attempt to contribute to the current knowledge of the brainstem reticular formation synaptic organization, the ultrastructure and distribution of synaptic terminal profiles on neurons in the ventral part of the oral pontine reticular nucleus (vRPO), the rapid eye movement (REM) sleep-induction site, were studied quantitatively.  

Activity of 44 mesencephalic locomotor area's (MLR) units and 38 pontine inhibitory area's (PIA) units was recorded during stimulation of the giganto-cellular reticular nucleus and oral pontine reticular nucleus inducing the hindlimb muscle tone inhibition in decerebrated rats.  

Regions with high proportions of neurons showing Type I responses and priming effects included the anterior dorsal tegmentum lateral to the central gray, the oral pontine reticular nucleus and the medial gigantocellular nucleus. Two regions, the anterior dorsal tegmentum and the oral pontine reticular nucleus, warrant further attention to determine their possible roles in the initiation of locomotion..  

Cholinergic microstimulation of the ventral part of the oral pontine reticular nucleus (vRPO) in cats generates and maintains paradoxical sleep.  

In rats, rapid eye movement (REM) sleep can be elicited by microinjection of vasoactive intestinal polypeptide (VIP) into the oral pontine reticular nucleus (PnO).  

Other brain structures participate in slow wave sleep organization; these include the basal forebrain, the oral pontine reticular nucleus, the deep cerebellar nuclei and the solitary tract nucleus.  

The main target of CRN axons is the contralateral pontine reticular formation, where collaterals terminate in the caudal pontine reticular nucleus (PnC) and, to a lesser degree, in the ventrolateral tegmental area, the oral pontine reticular nucleus, and the rostral and medial paralemniscal regions.  

In rats, rapid eye movement sleep can be induced by microinjection of either the cholinergic agonist carbachol or the neuropeptide vasoactive intestinal peptide into the oral pontine reticular nucleus. Sleep-waking cycles were analysed after infusion into the oral pontine reticular nucleus of vasoactive intestinal peptide (10 ng in 0.1 microl), carbachol (20 ng), atropine (200 ng) and pirenzepine (50, 100 ng), performed separately or in combination at 15-min intervals. Quantitative autoradiographic studies using [ 3H]quinuclidinyl benzylate (1 nM) and pirenzepine (0.5 microM) indicated that muscarinic receptors correspond to pirenzepine-insensitive binding sites in the oral pontine reticular nucleus. In vitro, vasoactive intestinal peptide (1-100 nM) significantly increased (+30-40%) the specific binding of [ 3H]quinuclidinyl benzylate to the oral pontine reticular nucleus in rat brain sections.  

Binding of [ 35S]GTPgammaS in the presence of carbachol, compared with basal binding, was significantly increased in the laterodorsal tegmental nucleus (75.7%), caudal pontine reticular nucleus (68.9%), oral pontine reticular nucleus (64.5%), pedunculopontine tegmental nucleus (55.7%), and dorsal raphe nucleus (54.0%) but not in the nucleus locus coeruleus.  

After gigantocellular reticular pars alpha injections, a very large and substantial number of labeled neurons were found in the deep mesencephalic reticular formation and oral pontine reticular nucleus, respectively.  

Rapid eye movement sleep can be elicited in the rat by microinjection of the cholinergic agonist carbachol into the oral pontine reticular nucleus. This hypothesis was tested by recording the sleep-wakefulness cycle in freely-moving rats injected with vasoactive intestinal peptide or its fragments (1-12 and 10-28) directly into the oral pontine reticular nucleus. Peptidergic mechanisms, possibly in association with cholinergic mechanisms, within the caudal part of the oral pontine reticular nucleus may play a critical role in the long-term regulation of rapid eye movement sleep in rats..  

At E19 fibers from the oral pontine reticular nucleus, the parvocellular reticular nucleus, the ventral gigantocellular reticular nucleus and the ambiguous nucleus first appeared in the lumbosacral cord.  

Microinjections of GABA into the ventral tegmental area (VTA), pedunculopontine tegmental nucleus (PPTg), and oral pontine reticular nucleus (PnO) also severely disrupted approach without decreasing consumption.  

Induction of REM sleep occurred when carbachol was infused specifically into the posterior oral pontine reticular nucleus (PnO).  

We report here that limited microinjections of a carbachol solution into the ventral part of the oral pontine reticular nucleus in the cat induce, with a short latency, a dramatic, long-lasting increase in paradoxical sleep. These two facts suggest that the ventral part of the oral pontine reticular nucleus is a nodal link in the neuronal network underlying paradoxical sleep mechanisms..  

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.  

Seven cats received diathermocoagulation lesions that destroyed between 13 and 100 percent of the CeSR; the remaining two cats, which suffered lesions in the paramedial region of the oral pontine reticular nucleus (RPO), were used to determine the effects on sleep/wakefulness states caused by damage to adjacent CeSR structures and/or passage fibres.  

There were significant reductions in the total number of SP+ neurons in the pedunculopontine tegmental nucleus (loss 43%), in the laterodorsal tegmental nucleus (loss 28%), in the oral pontine reticular nucleus (loss 41%) and in the median raphe nucleus (loss 76%).  

PH8-immunoreactive neurons were found in three cytoarchitectural regions: the median raphe nucleus (MnR), oral pontine reticular nucleus (PnO), and supralemniscal region (group B9).  

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

Some cases with posterior vermal and fastigial injections in addition showed labeled neurons bilaterally in the oral pontine reticular nucleus.  

Cells labeled with the peroxidase reaction product were located in gyrus propreus, gyrus genualis, nucleus accumbens, bed nucleus of the stria terminalis, bed nucleus of the anterior commissure, nucleus of the diagonal band, substantia innominata, anterior amygdaloid area, ventromedial hypothalamic area, paraventricular nucleus, perifornical hypothalamic area, lateral hypothalamic area, dorsal hypothalamic area, field of Forel, midbrain reticular formation, superior colliculus, ventral central grey, lateral central gray, locus coeruleus, parabrachial nuclei, nucleus of the lateral lemniscus, oral pontine reticular nucleus, and the dorsal raphe.  


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