title: 5-HT(2A) receptor-like protein is present in small neurons located in rat mesopontine cholinergic nuclei, but absent from cholinergic neurons.
abstract: The cholinergic neurons of the pedunculopontine and laterodorsal tegmental nuclei (PPN and LDN) increase their activity during wakefulness and REM sleep and interact with brainstem neurons containing serotonin (5-HT) and other amines. To determine whether mesopontine neurons that contain nitric oxide synthase (NOS), a marker for cholinergic cells, express 5-HT(2A) receptors, dual immunostaining for 5-HT(2A) receptor-like protein and NOS was employed with either peroxidase or fluorescent secondary probes. Within the PPN and LDN, different cells expressed 5-HT(2A) receptors and NOS. In addition to the lack of co-localization, the 5-HT(2A) receptor-expressing cells were smaller and less numerous than the adjacent NOS neurons. We propose that 5-HT(2A) receptor-expressing cells are local inhibitory interneurons whose one function is to ensure the reciprocal patterns of activity in subpopulations of mesopontine cholinergic and aminergic neurons.
authors.affiliation: Department of Animal Biology 205ED/VET, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104-4283, USA.
authors.forename: R
authors.initials: R
authors.lastname: Fay
authors.forename: L
authors.initials: L
authors.lastname: Kubin
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D000918:Antibody Specificity; D002452:Cell Count; D002799:Cholinergic Fibers / Q000378:metabolism* / Q000648:ultrastructure; D007150:Immunohistochemistry / Q000379:methods; D007395:Interneurons / Q000166:cytology / Q000378:metabolism*; D008297:Male; D009433:Neural Inhibition / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D011149:Pons / Q000166:cytology / Q000378:metabolism*; D011903:Raphe Nuclei / Q000166:cytology / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D044402:Receptor, Serotonin, 5-HT2A; D011985:Receptors, Serotonin / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism; D012890:Sleep / Q000502:physiology; D009435:Synaptic Transmission; D013681:Tegmentum Mesencephali / Q000166:cytology / Q000378:metabolism*; D014851:Wakefulness / Q000502:physiology
chemical_list: D044402:Receptor, Serotonin, 5-HT2A; D011985:Receptors, Serotonin; D009569:Nitric Oxide; D012701:Serotonin; D019001:Nitric Oxide Synthase; D000109:Acetylcholine