SR141716A induces in rats a behavioral pattern opposite to that of CB1 receptor agonists.
OBJECTIVE
To examine the acute actions of the CB1 cannabinoid receptor antagonist SR141716A [N-piperidino-5-(4-chlorophenyl)- 1-(2,4-dichlorophenyl)-4-methylpyrazole-3-carboxamide] on typical behavioral pattern of psychoactive cannabinoids in rats.


METHODS
At different time after injection the tail-flick response latency, the rectal temperature, the locomotor activity, and the immobility on a ring as well as the numbers of rears, self-grooming episodes (lasting 5 s), and fecal pellets were measured.


RESULTS
Acute administration of SR141716A (3 mg/kg i.p.) induced a significant increase in horizontal locomotor activity assayed by an activity meter, in stereotypic activity (such as rearing and self-grooming) and in defecation, and a decrease in nociceptive threshold recorded as tail-flick latency. This dose had no effect on ring immobility and did not change the body temperature.


CONCLUSIONS
These results demonstrate that this cannabinoid antagonist itself was inducing behavior opposite to that of CB1 receptor agonists.
Costa
B
B
Department of Pharmacology, Chemotherapy and Medical Toxicology, University of Milan, via Vanvitelli 32, Milan 20129, Italy.
Colleoni
M
M
D000818:Animals; D002186:Cannabinoids / Q000037:antagonists & inhibitors; D003672:Defecation / Q000187:drug effects; D008124:Locomotion / Q000187:drug effects; D008297:Male; D017288:Pain Threshold / Q000187:drug effects; D010880:Piperidines / Q000494:pharmacology*; D011720:Pyrazoles / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug / Q000037:antagonists & inhibitors*; D000077285:Rimonabant; D013239:Stereotyped Behavior / Q000187:drug effects*
D002186:Cannabinoids; D010880:Piperidines; D011720:Pyrazoles; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug; D000077285:Rimonabant