Propofol anaesthesia in mice is potentiated by muscimol and reversed by bicuculline.
We have examined the role of gamma-aminobutyric acid (GABA) neurones in propofol anaesthesia in mice using the righting reflex. Propofol i.p. increased the percentage of loss of the righting reflex in a dose-dependent manner with an ED50 value of 140 (95% confidence limits 123-160) mg kg-1 (n = 40; eight animals per dose, five doses per dose-response curve). The ED50 for propofol decreased significantly to 66 (58-75) mg kg-1 in the presence of the GABAA receptor agonist muscimol 1 mg kg-1 i.p. (n = 40) (P < 0.05). In contrast, the ED50 increased significantly to 240 (211-274) mg kg-1 in the presence of the antagonist bicuculline 5 mg kg-1 i.p. (n = 40) (P < 0.05). Our results suggest that propofol anaesthesia may be mediated, at least in part by GABA neurons.
Irifune
M
M
Department of Anaesthesiology, Hiroshima University School of Dentistry, Japan.
Sugimura
M
M
Takarada
T
T
Maeoka
K
K
Shimizu
Y
Y
Dohi
T
T
Nishikawa
T
T
Kawahara
M
M
D000779:Anesthetics, Local / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D018755:GABA Agonists / Q000494:pharmacology*; D018756:GABA Antagonists / Q000494:pharmacology*; D008297:Male; D051379:Mice; D009118:Muscimol / Q000494:pharmacology; D015742:Propofol / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D012018:Reflex / Q000187:drug effects
D000779:Anesthetics, Local; D018755:GABA Agonists; D018756:GABA Antagonists; D009118:Muscimol; D001640:Bicuculline; D015742:Propofol