Cross-tolerance between morphine- and nicotine-induced conditioned place preference in mice.
The acquisition of morphine and nicotine conditioned place preference (CPP) and cross-tolerance between the response of two drugs was studied in mice. A biased CPP paradigm was used to study the effect of the agents. Morphine (5 mg/kg) and nicotine (1 mg/kg) induced CPP. Naloxone (0.5, 1 and 2 mg/kg), but not mecamylamine (0.025, 0.05 and 0.1 mg/kg), induced conditioned place aversion (CPA). Both antagonists reversed CPP induced by morphine and nicotine. Administration of one daily dose of morphine (12.5, 25 or 50 mg/kg) for 3 days or nicotine (0.5, 1 or 2 mg/kg) three times a day for 12 days, in order to develop tolerance to the drugs, reduced the conditioning induced by morphine (5 mg/kg) or nicotine (1 mg/kg). CPA-induced by naloxone was reduced in animals, which were rendered tolerant to morphine (50 mg/kg) or nicotine (2 mg/kg). Mecamylamine, however, which did not induce any response in the nontolerant mice, elicited CPP in the tolerant animals. It is concluded that there may be a cross-tolerance between morphine- and nicotine-induced CPP.
Zarrindast
Mohammad Reza
MR
Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, P.O. Box 13145-784, Tehran, Iran. zarinmr@ams.ac.ir
Faraji
Nasrin
N
Rostami
Parvin
P
Sahraei
Hedayat
H
Ghoshouni
Hassan
H
D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004361:Drug Tolerance; D005260:Female; D008464:Mecamylamine / Q000494:pharmacology; D051379:Mice; D009020:Morphine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D009294:Narcotics / Q000494:pharmacology*; D009538:Nicotine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D018733:Nicotinic Antagonists / Q000494:pharmacology; D011957:Receptors, Opioid / Q000187:drug effects
D009292:Narcotic Antagonists; D009294:Narcotics; D018722:Nicotinic Agonists; D018733:Nicotinic Antagonists; D011957:Receptors, Opioid; D009270:Naloxone; D008464:Mecamylamine; D009538:Nicotine; D009020:Morphine