Effect of tetrandrine on morphine induced hyperactivity and reinforcement in mice

Abstract

After single administration of morphine and the motion activity was measured by ambulometer, conditioned place-preference paradigm was used to study the reinforcing effect of morphine, climbing behavior was used to evaluate the relation with Dopaminergic system and immediate early expression of c-fos gene was in brain was showed by immunohistochemical method. Single administration of morphine could induce hyperactivity, repeated treatment would produce a conditioned place-preference response, tetrandrine 30 or 60 mg/kg hypodermic injection could inhibit the morphine induced hyperactivity, 60 mg/kg could inhibit the conditioned place-preference response but no influence on climbing behavior in mice was found. Tetrandrine could inhibit the c-fos gene expression in nucleus accumbens, ventral tegmental and prefrontal cortex in place-preference model formed by morphine. Tetrandrine could inhibit the hyperactivity and conditioned place preference response induced by morphine, it might relate to reducing the c-fos gene expression in special area of brain in mice.