Intracerebral haloperidol potentiates the dorsal immobility response in the rat.

The effects of intracerebral microinjections of 4-[4-(4-chlorophenyl)-4-hydroxy-1-piperidinyl]-1-(4- fluorophenyl)-1-butanone (haloperidol) (1.0 microgram, 0.5 microliter) in five regions of the brain were tested on the duration of the dorsal immobility response (DIR) and the cling and bar catalepsy in the rat. The duration of the DIR was significantly potentiated (but not the cling and bar catalepsy) following 2-h postinjection of haloperidol in the caudate putamen, nucleus accumbens, and globus pallidus but not in the substantia nigra pars compacta or cortex. These data further expand the previous evidence of regional variations in dopamine to the effects upon inhibitory behaviors.