CB(1) receptor mediation of cannabinoid behavioral effects in male and female rats.
BACKGROUND
Cannabinoids have been shown to produce greater behavioral effects in female than male rats. Although central nervous system CB(1) receptors are known to mediate cannabinoid-induced behavioral effects in male rats, it is not known whether the same is true for females.


OBJECTIVE
To determine if cannabinoid-induced antinociception and catalepsy are similarly mediated by central CB(1) receptors in male and female rats.


METHODS
The ability of SR141716A, a CB(1) receptor selective antagonist, administered ICV (1-1000 microg) or IT (1-600 microg) to block 10 mg/kg IP delta(9)-THC-induced antinociception (paw pressure) and catalepsy (bar test), was compared in male and female rats.


RESULTS
Delta(9)-THC alone produced slightly greater antinociception, and significantly greater catalepsy in females than males. When administered ICV, SR141716A partially antagonized delta(9)-THC-induced antinociception in both females and males. IT SR141716A also antagonized delta(9)-THC-induced antinociception in both sexes; it was slightly more potent in males but equally effective in males and females. SR141716A antagonized delta(9)-THC-induced catalepsy in a similar manner in males and females when given ICV or IT.


CONCLUSIONS
These results confirm that delta(9)-THC-induced behavioral effects are mediated by central CB(1) receptors in male and female rats.
Program in Pharmacology and Toxicology, College of Pharmacy, Washington State University, Pullman, WA 99164-6534, USA.
Alan H
AH
Tseng
Rebecca M
RM
Craft
D000700:Analgesics / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D002375:Catalepsy / Q000139:chemically induced / Q000188:drug therapy; D013759:Dronabinol / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D005260:Female; D008297:Male; D010880:Piperidines / Q000008:administration & dosage / Q000494:pharmacology*; D011720:Pyrazoles / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D043884:Receptor, Cannabinoid, CB1 / Q000037:antagonists & inhibitors* / Q000502:physiology; D000077285:Rimonabant; D012737:Sex Factors
D000700:Analgesics; D010880:Piperidines; D011720:Pyrazoles; D043884:Receptor, Cannabinoid, CB1; D013759:Dronabinol; D000077285:Rimonabant