Physiology and Pharmacology

en The effect of morphine dependency on spatial learning and memory in male rat Experimental research article Experimental research article A Pourmotabbed1, M Tahmassian1, M Shahi1, H Karami Darabkhani1 and Y Fathollahi21. Dept. Physiology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah.2. Dept. Physiology, School of Medical Sciences, Tarbiat Modares University, Tehran.Abstract:The effect of morphine dependency on learning and memory is controversial. In the present study, the male rats wereused to evaluate the effects of morphine dependency on spatial learning and memory. Dependent animals receivedmorphine sulfate in drinking water for 20-30 days. Experiments were performed in two parts using Morris Water Maze(MWM). In part one, the effect of morphine dependency in normal and cold water was considered. In this part, animalswere divided into four groups in simple randomized manner. The first two groups (control and dependent), were studiedin normal water (20± 2 ◦C), and two another groups, were studied in cold water (10-12◦ C). Animals were studiedin MWM from day 21. In part two, rats were divided into two groups (withdrawal-normal and withdrawal-cold) toevaluate the effect of withdrawal of morphine. The condition was similar to the first part of experiments, but applicationof morphine was stopped from day 21. 48 h later, experiments in MWM was begun. In each group of animals, theparameters of spatial learning and memory were analyzed. Data were subjected to t-test and ANOVA.The results showed: 1- Morphine dependency facilitated spatial learning and memory in MWM. 2- Cold waterKeywords: Morphine dependency, Morris Water Maze, Spatial learning and memory, Withdrawal syndrome.reduced swim speed but facilitated the formation of spatial memory. 3-Cold water abolished the effect of morphineon spatial learning but facilitated the effect on formation of spatial memory. 4- Withdrawal syndrome reversed theeffects of morphine dependency. The mechanism(s) underling the phenomenon remains to be elucidated. 127 137 http://ppj.phypha.ir/browse.php?a_code=A-10-1-17&slc_lang=en&sid=1