Capsaicin evokes hypothermia independent of cannabinoid CB1 and CB2 receptors.
The present study investigated a potential role for cannabinoid CB(1) and CB(2) receptors in capsaicin-evoked hypothermia. Capsaicin (1 mg/kg, s.c.) caused rapid and significant hypothermia in rats. Pretreatment with SR 141716A (1, 2.5 and 5 mg/kg, i.p.), a CB(1) antagonist, or SR 144528 (1, 2.5 and 5 mg/kg, i.p.), a CB(2) antagonist, did not affect capsaicin-induced hypothermia. In separate experiments, the hypothermia caused by WIN 55212-2 (5 mg/kg, i.m.), a cannabinoid agonist, was not significantly altered by capsazepine (10 and 30 mg/kg, i.p.) or SB 366791 (2 mg/kg, i.p.), a novel TRPV1 antagonist. These data suggest that capsaicin causes hypothermia by a CB(1)- and CB(2)-independent mechanism, and that WIN 55212-2 causes hypothermia by a TRPV1-independent mechanism.
Ding
Zhe
Z
Department of Pharmaceutical Sciences and Pharmacology, Temple University School of Pharmacy and Medicine, 3307 North Broad Street, Philadelphia, PA 19140, USA.
Cowan
Alan
A
Rawls
Scott M
SM
D000813:Anilides / Q000494:pharmacology; D000818:Animals; D048588:Benzoxazines; D001831:Body Temperature / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000494:pharmacology; D001892:Camphanes / Q000494:pharmacology; D002211:Capsaicin / Q000494:pharmacology*; D002934:Cinnamates / Q000494:pharmacology; D007035:Hypothermia / Q000139:chemically induced* / Q000503:physiopathology; D008297:Male; D009025:Morpholines / Q000494:pharmacology; D009281:Naphthalenes / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D011720:Pyrazoles / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D043884:Receptor, Cannabinoid, CB1 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000187:drug effects*; D043885:Receptor, Cannabinoid, CB2 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000187:drug effects*; D000077285:Rimonabant; D050916:TRPV Cation Channels / Q000037:antagonists & inhibitors / Q000378:metabolism
D000813:Anilides; D048588:Benzoxazines; D002121:Calcium Channel Blockers; D001892:Camphanes; D002934:Cinnamates; D009025:Morpholines; C477659:N-(3-methoxyphenyl)-4-chlorocinnamanilide; D009281:Naphthalenes; D010880:Piperidines; D011720:Pyrazoles; D043884:Receptor, Cannabinoid, CB1; D043885:Receptor, Cannabinoid, CB2; C110630:SR 144528; D050916:TRPV Cation Channels; C493922:Trpv1 protein, rat; C070417:(3R)-((2,3-dihydro-5-methyl-3-((4-morpholinyl)methyl)pyrrolo-(1,2,3-de)-1,4-benzoxazin-6-yl)(1-naphthalenyl))methanone; D000077285:Rimonabant; D002211:Capsaicin