EN
In the present experiments the effect of perinatal lead exposure on development of morphine dependence in rats was examined. Female rats were gavaged daily with 0.1 % lead acetate solution. Lead ions were administered through pregnancy and two months through lactation. In the same time control animals received water. The development of morphine dependence was obtained by administration of increasing doses (10, 20, 30, 40, 50, 50 mg/kg, ip) of morphine for six consecutive days in lead intoxicated rats and in control animals. 20 min after the last injection of morphine the withdrawal signs were induced by application of naloxon at dose of 2 mg/kg, ip. Secondly, the development of morphine tolerance to antinociception activity was studied in the tail-flick test in lead intoxicated rats. Then rats received morphine (10 mg/kg, ip) for seven consecutive days and test was performed on 1st and 7th day of the experiment. The experiments have shown that in lead intoxicated rats morphine withdrawal signs (jumping, wet dog shakes) were significantly potentiated than in control animals. The morphine tolerance was also more expressed in lead intoxicate rats. The obtained results have shown that prenatal lead exposure intensify the effects of chronic treatment with morphine in rats.