Attenuation of hypothermic effects of ethanol by alpha 2-adrenoceptor blockers.
Effects of selective alpha 2-adrenoceptor antagonists, atipamezole and idazoxan, on ethanol-induced hypothermia were investigated in mice. Ethanol significantly reduced (P less than 0.001) core temperature whilst both alpha 2-adrenoceptor antagonists were without effect when administered alone. However, both the 1 and 3 mg/kg doses of atipamezole significantly (P less than 0.05) attenuated the ethanol-induced reduction in body temperature 20 and 40 min after administration. The 3 mg/kg dose of idazoxan (but not the 1 mg/kg dose) also significantly (P less than 0.05) attenuated ethanol's hypothermic effect 20 min after administration but this effect was not statistically significant at 40 min. In a subsequent experiment using lower doses of atipamezole (0.03-1.0 mg/kg) the attenuation of ethanol-induced hypothermia caused by atipamezole was found to be dose-related. The effect of the benzodiazepine inverse agonist Ro 15-4513 on ethanol-induced hypothermia was also investigated. This compound possessed an intrinsic hypothermic action but neither attenuated nor enhanced the hypothermic effect of ethanol. These results suggest that alpha 2-adrenoceptor can, at least partially, modulate the hypothermic effects of ethanol.
Durcan
M J
MJ
Laboratory of Clinical Studies, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD 20892.
Wozniak
K M
KM
Lister
R G
RG
Linnoila
M
M
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D001386:Azides / Q000494:pharmacology; D001569:Benzodiazepines / Q000494:pharmacology; D001831:Body Temperature / Q000187:drug effects*; D004146:Dioxanes / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000037:antagonists & inhibitors*; D019329:Idazoxan; D007093:Imidazoles / Q000494:pharmacology; D008297:Male; D051379:Mice; D010424:Pentobarbital / Q000494:pharmacology; D013997:Time Factors
D000317:Adrenergic alpha-Antagonists; D001386:Azides; D004146:Dioxanes; D007093:Imidazoles; C050701:atipamezole; D001569:Benzodiazepines; D000431:Ethanol; C042957:Ro 15-4513; D010424:Pentobarbital; D019329:Idazoxan