Effects of Desipramine Treatment upon Central Adrenoceptor Function in Normal Subjects

Abstract

Six normal subjects were given clonidine infusions after 0, 1 and 3 wk of treatment with desipramine (2 mg/kg) and at 1 and 3 wk after withdrawal from desipramine. The sedative and hypotensive effects of clonidine were inhibited after 1 and 3 wk of desipramine treatment, and returned to normal after stopping treatment without any rebound increase. Such a time-course can be explained in terms of the acute effects of the drug, no adaptive changes at receptors need be invoked. By contrast, the growth hormone response to clonidine tended to be increased after 1 wk of desipramine, reduced after 3 wk of treatment, and further reduced after discontinuation. Such a time-course is consistent with an adaptive down regulation at .alpha.2 adrenoceptors in response to their acute stimulation, due to norepinephrine re-uptake blockade.