Prazosin selectively antagonizes neuronal responses mediated by alpha1-adrenoceptors in brain.

The ability of systemically and locally administered prazosin to block alpha 1-adrenoceptors was examined in two brain areas in the rat. Using single unit recording of neurons in the lateral geniculate and dorsal raphe nuclei, evidence was obtained for the selective blockade of alpha 1-adrenoceptors by both intravenous and iontophoretic prazosin. Since effective systemic doses of prazosin were within the clinical range, it appears likely that brain alpha 1-adrenoceptors would be blocked during prazosin therapy in humans.