Operant behaviour performance changes in rats after prenatal and postnatal exposure to heavy metals.

In a previous communication we described the effect of methylmercury chloride, given to pregnant rats on days 6 through 9 after conception, on the learning ability of their adult offspring. It was found that a total dose of 0.04 mg/kg induced performance deficits. In this study the experiments were extended to lead acetate, thallium sulphate and damium chloride given either prenatally or postnatally. The results of these instrumental behavioural studies show a functional impairment of the brain after doses of heavy metal compounds where no toxic effects have been observed so far with other methods. Prenatal treatment was more effective than a postnatal exposure