Alpha 2-adrenoceptor antagonists block the stimulant effects of cocaine in mice.
In the present study we have investigated the effects of the alpha 2-adrenoceptor antagonist idazoxan and its 2-ethoxy derivative RX811059 on the locomotor activity induced by cocaine in mice. The stimulant effects of cocaine (15 mg/kg i.p.) were significantly antagonised by idazoxan (3 mg/kg i.p.) and RX811059 (1 mg/kg i.p.) and also initially suppressed by idazoxan (1 mg/kg i.p.) and RX811059 (0.3 mg/kg i.p.). The alpha 2-adrenoceptor antagonists had no effect on locomotion when given alone. These results suggest that noradrenergic mechanisms may play a role in the stimulant effects of cocaine and that alpha 2-adrenoceptor antagonists like idazoxan may be of some benefit in the clinical management of cocaine abuse.
Reckitt & Colman Psychopharmacology Unit, Department of Pharmacology, School of Medical Sciences, Bristol, U.K.
H C
HC
Jackson
I J
IJ
Griffin
D J
DJ
Nutt
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D003042:Cocaine / Q000037:antagonists & inhibitors*; D004146:Dioxanes / Q000494:pharmacology*; D019329:Idazoxan / Q000031:analogs & derivatives; D008297:Male; D051379:Mice; D009043:Motor Activity / Q000187:drug effects*
D000317:Adrenergic alpha-Antagonists; D004146:Dioxanes; C065483:ethoxyidazoxan; D003042:Cocaine; D019329:Idazoxan