Nicotinic cholinoceptor-mediated excitatory postsynaptic potentials in rat nucleus ambiguus.
In rat brainstem slice preparations, intracellular recording from neurons (n = 39) in the compact formation of the nucleus ambiguus (AMBc) revealed spontaneous and miniature excitatory postsynaptic potentials (EPSPs; n = 11) that, along with acetylcholine-induced depolarization, were enhanced by physostigmine (10 microM; n = 2) and blocked by dihydro-beta-erythroidine 1-5 pmol (n = 4). Retrograde neuronal tracing combined with choline acetyltransferase immunocytochemistry demonstrated that the AMBc receives a projection from a subpopulation of cholinergic neurons in the zona intermedialis reticularis parvicellularis. Electrical stimulation of this region in slices evoked fast EPSPs in AMBc neurons (n = 23) that were inhibited by dihydro-beta-erythroidine 2-5 pmol (n = 8), but not by methscopolamine 1 pmol (n = 2). The present findings strongly support the existence of a cholinergic nicotinic synapse mediating fast transmission in brainstem vagal motoneurons.
Zhang
M
M
Faculty of Medicine, Memorial University of Newfoundland, St. John's, Canada.
Wang
Y T
YT
Vyas
D M
DM
Neuman
R S
RS
Bieger
D
D
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001933:Brain Stem / Q000166:cytology / Q000502:physiology; D002795:Choline O-Acetyltransferase / Q000276:immunology / Q000378:metabolism; D004079:Dihydro-beta-Erythroidine / Q000494:pharmacology; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007478:Iontophoresis; D008297:Male; D008526:Medulla Oblongata / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D009046:Motor Neurons / Q000187:drug effects; D019832:N-Methylscopolamine; D009474:Neurons / Q000201:enzymology / Q000502:physiology; D010276:Parasympatholytics / Q000494:pharmacology; D010830:Physostigmine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011978:Receptors, Nicotinic / Q000187:drug effects / Q000502:physiology*; D012154:Reticular Formation / Q000187:drug effects / Q000502:physiology; D012602:Scopolamine Derivatives / Q000494:pharmacology; D013569:Synapses / Q000187:drug effects*
D010276:Parasympatholytics; D011978:Receptors, Nicotinic; D012602:Scopolamine Derivatives; D004079:Dihydro-beta-Erythroidine; D010830:Physostigmine; D002795:Choline O-Acetyltransferase; D000109:Acetylcholine; D019832:N-Methylscopolamine