title: Electrophysiological evidence for cholinoceptive neurons in the medial vestibular nucleus: studies on rat brain stem in vitro.
abstract: Electrophysiological studies were performed to determine whether or not cholinoceptive neurons are present in the rat medial vestibular nucleus (MVN) using brainstem slice preparations. Fifty-three MVN neurons, whose activities were extracellularly recorded, fired spikes spontaneously and regularly with an interspike interval of 180 +/- 27 ms (mean +/- S.E.M.) and a coefficient of variation of 0.11 +/- 0.02. Intracellularly recorded neurons also exhibited similar spontaneous and regular generation of action potentials. Carbachol dose-dependently increased the spontaneous firing, although the firing rate was decreased in a few neurons. The addition of atropine reduced the firing rate, and dose-dependently attenuated the carbachol-induced excitation of the neurons. In a low Ca2+ and high Mg2+ medium, carbachol also increased the firing rate. These results indicate that the MVN contains neurons with spontaneous and regular firing, and that the excitability of these neurons is regulated by a cholinergic muscarinic mechanism.
authors.affiliation: Department of Pharmacology, Faculty of Medicine, Kyoto University, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ujihara
authors.forename: A
authors.initials: A
authors.lastname: Akaike
authors.forename: M
authors.initials: M
authors.lastname: Sasa
authors.forename: S
authors.initials: S
authors.lastname: Takaori
mesh_terms: D000818:Animals; D001285:Atropine; D002217:Carbachol; D004594:Electrophysiology; D008297:Male; D009474:Neurons / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains; D011950:Receptors, Cholinergic / Q000032:analysis* / Q000502:physiology; D014726:Vestibular Nuclei / Q000032:analysis*
chemical_list: D011950:Receptors, Cholinergic; D001285:Atropine; D002217:Carbachol