The effects of perinatal cadmium exposure on behavioral sensitization to morphine

Abstract

This study examined the effects of developmental cadmium exposure on morphine-induced locomotor activity. Adult female rats were exposed to 0 ppm, 25 ppm and 50 ppm cadmium via an adulterated food source for 30 days prior to breeding. This exposure continued throughout gestation and for the initial 15 days of lactation. Male pups of the dams were then administered 10 mg/kg morphine or vehicle injections at PND 60 and locomotor activity was monitored. Days 1,7, and 14 produced no separation of exposure groups. On Day 21 attenuation of morphine-induced behavioral sensitization was evident among animals in the 25 ppm and 50 ppm exposure groups. Administration of dopamine Dl receptor-type antagonist SCH 23390 produced a dose-related decrease in locomotor activity across all groups. D2 receptor-type antagonist eticlopride showed no significant separation of responding among exposure groups. Context effects were not found to play a role in these findings.