Dopaminergic antagonism and catalepsy in the developing rat

The cataleptic effect of the dopaminergic blockers spiroperidol and haloperidol was investigated in developing rats. Both neuroleptics were found to produce less catalepsy in 15 day old rats than in either 10 or 20 day old animals. It is proposed that the decrement in catalepsy occurring between 10 and 15 days of age is related to increased dopaminergic activity in the neostriatum. The reversal of this phenomenon by 20 days may be a consequence of maturation of cholinergic local circuit neurons.