title: Peripheral electric stimulation attenuates the expression of cocaine-induced place preference in rats.
abstract: The present study was designed to investigate the effect of peripheral electrical stimulation (PES), with high (100 Hz) or low (2 Hz) frequencies, on the expression of cocaine-induced conditioned place preference (CPP). Rats were trained with cocaine (0.1-10 mg/kg, i.p.) under a biased paradigm in a three-compartment chamber for the development of a CPP. One day following the last conditioning, the total time spent in each compartment was recorded after the deliverance of PES. Naloxone (1, 5, and 10 mg/kg, i.p.) was applied to investigate whether endogenous opioid receptor pathways play any role in the effect of PES. It was found that (1). 1 mg/kg and higher doses of cocaine, but not 0.5 mg/kg, produced significant place preference, (2). cocaine-induced CPP, once developed, maintained for more than 13 days in a cocaine-free state, (3). PES of 100 Hz, but not 2 Hz, significantly attenuated the expression of cocaine-induced CPP (P<0.01), (4). PES per se did not influence the natural place preference in rats, and (5). the inhibition of cocaine CPP induced by 100 Hz PES could be reversed by naloxone pre-treatment at 10 mg/kg, but not at lower doses. These results suggest that PES could inhibits cocaine-induced CPP in a frequency-dependent manner. This effect is probably mediated by an endogenous kappa-opioid mechanism.
authors.affiliation: Neuroscience Research Institute, Beijing University, 38 Xueyuan Road, 100083, Beijing, PR China.
authors.forename: Yan-Hua
authors.initials: YH
authors.lastname: Ren
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.forename: Fei
authors.initials: F
authors.lastname: Luo
authors.forename: Cai-Lian
authors.initials: CL
authors.lastname: Cui
authors.forename: Ji-Wang
authors.initials: JW
authors.lastname: Zheng
authors.forename: Ji-sheng
authors.initials: JS
authors.lastname: Han
mesh_terms: D000818:Animals; D003042:Cocaine / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects; D003213:Conditioning, Psychological / Q000187:drug effects; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D017933:Peripheral Nervous System; D051381:Rats; D017207:Rats, Sprague-Dawley; D017473:Receptors, Opioid, kappa / Q000378:metabolism
chemical_list: D018765:Dopamine Uptake Inhibitors; D009292:Narcotic Antagonists; D017473:Receptors, Opioid, kappa; D009270:Naloxone; D003042:Cocaine