Chronic haloperidol during development attenuates dopamine autoreceptor function in striatal and mesolimbic brain regions of young and older adult rats.

The effects of chronic haloperidol administration during the prenatal and preweanling periods on dopamine autoreceptor function were examined in striatum, olfactory tubercles, and nucleus accumbens of young (2-3 month) and older (12-13 month) adult rats. In striatum of young and older adult rats that had been chronically treated with haloperidol early in life, as well as in the nucleus accumbens of older adults receiving early chronic haloperidol, gamma-butyrolactone (GBL) did not induce significant increases in dopamine levels. In olfactory tubercles of young adults that had received early chronic treatment with haloperidol, apomorphine pretreatment failed to reverse the observed GBL-induced increase in dopamine levels. Thus, dopamine autoreceptor function appears to be attenuated in rats chronically treated with haloperidol during early development, in contrast to reports of autoreceptor supersensitivity following neuroleptic treatment in adulthood.