Sleep patterns after carbachol delivery in the ventral oral pontine tegmentum of the cat

Muscarinic‐2 and orexin‐2 receptors on GABAergic and other neurons in the rat mesopontine tegmentum and their potential role in sleep–wake state control

“…By in vitro receptor autoradiography, a relatively homogeneous pattern of radiolabeled M2R ligand binding had previously been noted in the pons (Baghdoyan, 1997). Such a wide distribution of M2R-bearing cells may explain why carbachol has been shown to elicit PS or some of its components when injected into many different subregions of the pontine tegmentum encompassing central, lateral, ventral, and dorsal regions such as to include all of the PnO and lateral pontine tegmentum as delineated here (George et al, 1964;Baghdoyan et al, 1984Baghdoyan et al, , 1987Gnadt and Pegram, 1986;VanniMercier et al, 1989;Yamamoto et al, 1990;Vertes et al, 1993;Reinoso-Suarez et al, 1994;Bourgin et al, 1995;Garzon et al, 1998;Horner and Kubin, 1999). Indeed, whereas some studies indicate that the shortest latency and longest duration bouts of PS are elicited by carbachol injections into the dorsal lateral pontine tegmentum (Vanni-Mercier et al, 1989), others indicate that these are elicited by injections into the ventral PnO (Reinoso-Suarez et al, 1994).…”

“…Injection of the ACh agonist carbachol into the mesopontine tegmentum of cats elicited a state of PS with muscle atonia (George et al, 1964). Multiple studies subsequently performed in cats (Baghdoyan et al, 1984(Baghdoyan et al, , 1987Vanni-Mercier et al, 1989;Yamamoto et al, 1990;Reinoso-Suarez et al, 1994;Garzon et al, 1998) and then rats (Gnadt and Pegram, 1986;Vertes et al, 1993;Bourgin et al, 1995;Horner and Kubin, 1999) indicated that the most effective site for this effect was in the oral pontine field (PnO) of the reticular formation and adjacent lateral pontine tegmentum. In this same region, endogenous ACh is released in higher concentrations during nat-ural PS than during waking and slow wave sleep (SWS) (Kodama et al, 1990).…”

Serotonergic connections to the ventral oral pontine reticular nucleus: Implication in paradoxical sleep modulation

“…The vRPO is thought to orchestrate the wide neural network responsible for the organization and maintenance of PS (Reinoso-Suá rez et al, 1994). In experiments carried out in our laboratory in freely moving cats, we have seen that microinjections of very small volumes of carbachol at different concentrations, produce an immediate and long-lasting increase of PS that is similar to spontaneous PS, but only when they are located in vRPO (Reinoso-Suá rez et al, 1994;Garzón et al, 1997Garzón et al, , 1998. However, injections located in LDT, periLC␣, RPC, and other structures of the pontine tegmentum, although giving rise to some of the typical events of PS, do not produce all of the bioelectrical and behavioral manifestations that characterize PS when they appear in natural harmony (Reinoso-Suá rez et al, 1994;Garzón et al, 1996;De Andrés et al, 1998).…”

“…More recently, Sakai and Onoe (1997) have defined the caudal and ventral part of the peri ␣ as the PS-inducing structure. However, our studies, using local delivery of small amounts and doses of carbachol, show that the ventral part of the oral pontine reticular nucleus (vRPO) is the structure that induces, with short latency, and maintains PS (Reinoso-Suá rez et al, 1994;Garzón et al, 1997Garzón et al, , 1998. The dorsal oral pontine tegmentum (LC␣/periLC␣) would thus be involved in the control of partial bioelectrical events characteristic of PS, such as PGO activity or atonia (Sakai et al, 1977(Sakai et al, , 1980Paré et al, 1990;Reinoso-Suá rez et al, 1994;de Andrés et al, 1998).…”

Dendritic and axonal targeting of the vesicular acetylcholine transporter to membranous cytoplasmic organelles in laterodorsal and pedunculopontine tegmental nuclei

“…Many of these axon terminals may derive from glutamatergic neurons within the pontine reticular formation, which are known to project widely to the PPT and LDT nuclei (Lai et al, 1993). In particular, the ventral part of the nucleus reticularis pontis oralis is reciprocally connected with these nuclei (Reinoso-Suá rez et al, 1994) and is a highly-selective area for inducing the appearance of REM sleep (ReinosoSuá rez et al, 1994;Garzón et al, 1997Garzón et al, , 1998. Thus, as discussed in the previous section, local dendritic release of acetylcholine to modulate excitatory input from the ventral part of the nucleus reticularis pontis oralis could trigger the signal leading to activation of mesopontine cholinergic cells and appearance of REM sleep events such as PGO waves and EEG desynchronization.…”