Regional localization of halopemide, a new psychotropic agent, in the rat brain.

Halopemide is a new psychotropic agent, structurally related to the neuroleptics of the butyrophenone type, but with a different phamacological and clinical profile. The concentration of halopemide in the rat brain is about 10 times less than that of R29800, its chemical congener and of spiperone, both typical neuroleptics. In the pituitary gland, however, the levels are the same. The distribution profile of halopemide in rat brain deviates from that of neuroleptics. The highest level of halopemide is found in septal and thalamic areas whereas the neuroleptics are concentrated in the caudate nucleus, the nucleus accumbens and the tuberculum olfactorium. Subcellular distribution experiments show that in the caudate nucleus halopemide is far less particle-bound that are the neuroleptic agents.