Effects of morphine-treated fetal mice on spatial learning after birth

Abstract Background: Drug abuse during pregnancy is a growing problem in all developed countries worldwide. Maternal drug abuse affects the developing systems and the associated long-term effects can persist untill adulthood, decreasing the rate of their maturation. Objective: To determine the effects of prenatal morphine exposure on spatial learning Methods: Eighteen pregnant rats were divided into morphine, saline, and control groups. Morphine or saline was administrated (S.C) to female rats twice a day (at 12-hr intervals) during the days 11-18 of their gestational period (5 mg/kg morphine for the first 3 days and 10 mg/kg for further 5 days). Pups (P90, n=6) were trained in an 8-arm radial maze apparatus.The data were analyzed statistically using Chi-square test. Findings: The results indicated that prenatal morphine exposure causes a reduction in the time needed to learn these trials however, they needed more time to complete regular trials. Conclusion: Prenatal morphine exposure impairs normal spatial learning.