TY - JOUR T1 - Role of Gabaa Receptors of CA1 Regions of Hippocamp in The Acquisition and - Expression of Morphine - Induced Conditioned Place Preference TT - نقش گیرنده‌های GABAA نواحی CA1 هیپوکامپ در اکتساب و بیان ترجیح مکان شرطی شده ناشی از مرفین JF - icss JO - icss VL - 6 IS - 3 UR - http://icssjournal.ir/article-1-88-en.html Y1 - 2004 SP - 37 EP - 48 N2 - Objective: Hippocamp is a major reward-based learning center. Considering broad distribution of GABAA receptors in CA1 region of dorsal hippocamp, one can guess that they might play a role in reward-based learning. In the present study, the effects of bilateral intra-hippocampal injections of either GABAA receptor agonist or antagonist on the acquisition and- expression of morphine- induced conditioned place preference were evaluated in vitro on male Wistar rats. Method: In this interventional in vitro experiment, adult male Wistar rats weighing 200-240 grams were used. All of the study animals were bilaterally cannulated in their CA1 regions of dorsal Hippocamp by a stereotaxic machine. After a recovery period, they all underwent conditioning training and induced "conditioned place preferene" (CPP). The method used for CPP included a 5-day course with the following three separate phases: 1- preconditioning phase; 2- conditioning phase; and 3- testing or reward - expression phase. Results: Subcutaneous injection of different doses of morphine in a frequency - based method induced a conditioned place preference (CPP). Injection of mosimol as a GABAA receptor agonist in CA1 regions could significantly suppress morphine - induced CPP. Bilateral injections of different doses of bicoculine into the CA1regions of hippocamp, together with an ineffective dose of morphine resulted in the induction of a significant CPP. Mosimol or bicoculine alone did not have any effect on place conditioning. Our findings also disclosed that the induced reaction by bilateral injection ofmosimol into the CA1 regions could be reversed if pre-treated with bicoculin. On the other hand, bilateral injections of mosimol into the CA1 regions could be reversed if pre-treated with bicoculin. On the other hand, bilateral injections of mosimol or bicoculing into the CA1 regions significantly reduced - expression of morphin - induced CPP; however, it did not affect movement activities in the test phase. Conclusion: Results of the present study revealed that GABAA receptors of the CA1 region of hippocampe play an important role in the acquisition and expression of morphine- induced conditioned place preference. M3 ER -