Effects of ritanserin on the rewarding properties of d-amphetamine, morphine and diazepam revealed by conditioned place preference in rats.
The possibility that 5-HT2 receptors mediate the reinforcing properties of d-amphetamine, morphine and diazepam was investigated in rats, using ritanserin, a 5-HT2 antagonist, and the conditioned place preference paradigm. Ritanserin 1 or 2.5 mg/kg did not cause place conditioning. Place preference induced by 1.5 mg/kg d-amphetamine and 2 mg/kg morphine was inhibited and attenuated respectively by pretreatment with 2.5 mg/kg ritanserin. Diazepam- (1 mg/kg) induced place preference was completely blocked by both doses of ritanserin. Ritanserin pretreatment failed to influence amphetamine-induced hyperlocomotion, morphine-induced analgesia and diazepam-induced increased open arm exploration of rats on the elevated plus maze. These data are discussed in terms of (a) the possibility that serotoninergic mechanisms have a role in mediating reinforcement and (b) the relationship between appetitive properties and specific behavioral effects of psychostimulants, opiates and anxiolytics.
Nomikos
G G
GG
Department of Pharmacology, Medical School, University of Athens, Greece.
Spyraki
C
C
D000698:Analgesia; D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects*; D003913:Dextroamphetamine / Q000494:pharmacology*; D003975:Diazepam / Q000494:pharmacology*; D005106:Exploratory Behavior / Q000187:drug effects; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects*; D010880:Piperidines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D012054:Reinforcement, Psychology; D012201:Reward; D016713:Ritanserin; D012702:Serotonin Antagonists / Q000494:pharmacology*
D010880:Piperidines; D012702:Serotonin Antagonists; D016713:Ritanserin; D009020:Morphine; D003975:Diazepam; D003913:Dextroamphetamine