TY - JOUR T1 - The Role of Muscarinic Receptors in Ventral Tegmental Area in The Acquisition of Morphine-Induced Conditioned Place Preference in Mice TT - نقش گیرنده‌های موسکارینی ناحیه تگمنتوم شکمی، در اکتساب ترجیح مکان شرطی‌شده ناشی از مورفین در موش بزرگ آزمایشگاهی JF - icss JO - icss VL - 8 IS - 4 UR - http://icssjournal.ir/article-1-236-en.html Y1 - 2007 SP - 1 EP - 10 KW - Morphine KW - Physostigmine. Atropine KW - Conditioned Place Prej'erence KW - Ventral Tegmental Area N2 - Objective: Ventral Tegmental Area is the main center for reward. In this study the effects of intra-ventral tegmental area (VTA) injections of muscarinic acetylcholine receptor agonists and antagonists on morphine-induced conditioned place preference (CPP) were investigated. Method: The cannulas were implanted (bilaterally) in the VTA by Stereotaxic instrument in Wistar rats. All animals were allowed one week to recover before CPP. Unbiased CPP was induced by carrying out a five day schedule comprised of preconditioning, conditioning and testing phases. Results: Injections of different doses of morphine induced a significant dose-dependent CPP. Intra-VT A injection of an anticholinesterase, physostigmine with an ineffective dose of morphine elicited a significant CPP in a dose dependent method. Intra-VTA administration of muscarinic acetylcholine receptor antagonist, atropine inhibited both morphine-induced place preference and the reinforced response induced by physostigmine. The injection of physostigmine alone into the VTA produced a significant place aversion; whereas atropine did not have such an effect. High doses of physostigmine or atropine alone as well as the simultaneous injection of atropine and physostigmine with an ineffective dose of morphine decreased locomotor activity. Conclusion: The muscarinic acetylcholine receptors in the VTA have a critical role in the rewarding effects of morphine. M3 ER -