Modulatory roles of GABAergic mechanisms in post-rotatory nystagmus in the rabbit.
1. To determine how the GABAergic mechanism operates in the generation of post-rotatory nystagmus, an experiment was performed with GABAergic drugs in rabbits. 2. Subconvulsive doses of picrotoxin (0.3-0.6 mg/kg, i.v.) and bicuculline (0.1 mg/kg, i.v.) decreased the number of post-rotatory nystagmus beats, whereas strychnine sulphate, at a subconvulsive dose (0.1 mg/kg i.v.), increased it. 3. Diazepam (1 mg/kg, i.v.) remarkably increased the number of post-rotatory nystagmus beats. Pretreatment with picrotoxin (0.45 mg/kg, i.v.), bicuculline (0.1 mg/kg, i.v.) or semicarbazide-HCl (180 mg/kg, i.v.) antagonized the effects of diazepam (1 mg/kg, i.v.). 4. GABAergic mechanisms may play a modulatory role in the production of nystagmus rhythm. Strychnine-sensitive neurons involved in the vestibular mechanism may behave in a different manner from picrotoxin-sensitive neurons.
Ishikawa
M
M
Pharmacology Section, Nippon Kayaku Co., Ltd, Tokyo, Japan.
Miyazaki
H
H
Fukuda
H
H
D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D003975:Diazepam / Q000494:pharmacology; D009759:Nystagmus, Pathologic / Q000503:physiopathology*; D010852:Picrotoxin / Q000494:pharmacology; D011817:Rabbits; D012399:Rotation; D012663:Semicarbazides / Q000494:pharmacology; D013331:Strychnine / Q000494:pharmacology; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D001640:Bicuculline; D003975:Diazepam; D010852:Picrotoxin; D012663:Semicarbazides; D013331:Strychnine; D005680:gamma-Aminobutyric Acid