Effects of ethanol on vestibular nucleus neurons responding to sinusoidal rotation.
Effects of ethanol applied by electro-osmosis were examined on the rat vestibular nucleus neurons responding to vestibular nerve stimulation and horizontal sinusoidal rotation. Ethanol (50-150 nA) inhibited the neurons monosynaptically activated by vestibular nerve stimulation and also suppressed the activity of the type I neuron, which responded with an increase in firing on ipsilateral rotation and a decrease on contralateral rotation. However, the drug did not affect the type II neuron, which showed the opposite response to the ipsi- and contralateral rotation compared with the type I neuron. Iontophoretic application of atropine (25-50 nA) inhibited spontaneous and rotation-induced firing in both type I and II neurons. These results suggest that ethanol inhibits the type I neuron projecting to the abducens nucleus, thereby impairing the vestibulo-ocular reflex.
Sasa
M
M
Department of Pharmacology, Faculty of Medicine, Kyoto University, Japan.
Shimizu
H
H
Yoshida
S
S
Takaori
S
S
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D000431:Ethanol / Q000494:pharmacology*; D008297:Male; D009474:Neurons / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D012399:Rotation; D014726:Vestibular Nuclei / Q000187:drug effects*
D000431:Ethanol; D001285:Atropine