POTENTIATING EFFECTS OF METHAMPHETAMINE ON THE HYPERACTIVITY OF MICROENCEPHALIC RATS TREATED PRENATALLY WITH METHYLAZOXYMETHANOL - POSSIBLEIMPLICATION OF HYPERDOPAMINERGIA

Microencephalic rats induced by methylazoxymethanol (MAM) were observe d to have notable hyperactivity compared to control rats, as measured by several behavioral parameters in an automated field apparatus. Acut e injection of the stimulant drug, methamphetamine (MAP), produced an increase in the incidence of locomotion and rearing in control rats, a nd this stimulatory effect of MAP on motor activity was markedly poten tiated in MAM rats. Chronic MAP treatment did not change D-1 or D-2 do pamine receptor densities in either control or MAM rats. From these re sults, it was suggested that augmented dopaminergic functions may cont ribute to the hyperactivity seen in MAM rats.