Failure of ritanserin to block the discriminative or reinforcing stimulus effects of cocaine.
Ritanserin, a 5-HT2/1C antagonist, has been suggested to reduce the preference for cocaine in rats. In the present experiment, the action of ritanserin was investigated in locomotor activity, cocaine drug discrimination, and cocaine self-administration paradigms in rats. A low dose of ritanserin (1.0 mg/kg) was without effect on locomotor activity, while a higher dose (10.0 mg/kg) reduced both horizontal and vertical locomotor activity counts during the first 30 min of the test session. Ritanserin (0.32-32 mg/kg) did not significantly affect the discrimination of 10 mg/kg of cocaine, nor did a dose of 10.0 mg/kg significantly modify the dose-effect curve for cocaine discrimination. Ritanserin (1.0 and 10.0 mg/kg) had no significant effect on the dose-response curve for cocaine self-administration. Thus, ritanserin was without effect against either the discriminative or reinforcing stimulus effects of cocaine, suggesting that ritanserin has limited efficacy as a potential treatment for cocaine abuse.
Peltier
R L
RL
Department of Pharmacology, University of North Texas HSC at Fort Worth 76107-2699.
Emmett-Oglesby
M W
MW
Thomas
W H
WH
Schenk
S
S
D000818:Animals; D003042:Cocaine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects*; D004192:Discrimination, Psychological / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D011916:Rats, Inbred F344; D017207:Rats, Sprague-Dawley; D012055:Reinforcement Schedule; D012054:Reinforcement, Psychology; D016713:Ritanserin / Q000494:pharmacology*; D012646:Self Administration
D016713:Ritanserin; D003042:Cocaine