[Pharmacological assessment of functional alterations in the brain of rats exposed prenatally to methylazoxymethanol].

Functional development of the brain of rats exposed to methylazoxymethanol (MAM) at a dose of 1, 5 or 20 mg/kg, i.p., on day 15 of fetal life was assessed using pharmacological responses to several CNS acting drugs. In the rats treated with 20 mg/kg of MAM, the following results were observed: A marked decrease in the rearing activity in an openfield, failure of the development of supersensitivity in cataleptic response to haloperidol administered weekly, an increase in the head down sniffing frequency after apomorphine administration, prolongation of pentobarbital-induced sleeping time, a decrease in the seizure threshold to picrotoxin and kainic acid, and a significant decrease in the growth rate. In addition, the rats administered 1 mg/kg of MAM, which have been reported to detect no biochemical changes in the brain, exhibited different responses to the drugs used: A marked decrease in the rearing activity, nearly normal threshold to picrotoxin and kainic acid, a pronounced hypothermia after chlorpromazine administration, and no significant change in the brain weights. The results suggest that rats exposed to MAM in varying doses would be useful for evaluating the developmental process of neurons and its unification.