Synthetic double-stranded RNA polyinosinic-polycytidylic acid augments morphine-induced conditioned place preference in rats.
Three experiments were performed to study the effects of immune challenge on the rewarding properties of opiates. Intraperitoneal injection of polyinosinic-polycytidylic acid (Poly I:C, 1 mg/kg) was used to trigger an immune challenge. Conditioned place preference (CPP) in rats trained with alternating subcutaneous injections of morphine (5 mg/kg) and saline was used to assess the rewarding effect of morphine. Poly I:C administered before CPP training had no effects on CPP acquisition. Poly I:C administered during CPP training enhanced CPP acquisition. Poly I:C administered after morphine-induced CPP acquisition retarded CPP extinction. These results show that the immune challenge by Poly I:C augmented morphine CPP in rats depending on the onset time of the challenge. The findings suggest that immune challenge may enhance the rewarding properties of opiates.
Zhang
Lei
L
School of Information and Communication Engineering, North University of China, Taiyuan, China.
Chen
Suqing
S
Liu
Hongyu
H
Lu
Lin
L
Zhai
Haifeng
H
D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005108:Extinction, Psychological / Q000187:drug effects; D007109:Immunity / Q000187:drug effects; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009294:Narcotics / Q000494:pharmacology*; D011070:Poly I-C / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012201:Reward
D000998:Antiviral Agents; D009294:Narcotics; D009020:Morphine; D011070:Poly I-C