Influence of centrally administered α- and γ2-melanocyte-stimulating hormone on hypothalamic blood flow autoregulation in the rat

Abstract

The effect of intracerebroventricularly (i.c.v.) administered α-melanocyte-stimulating hormone (MSH) and γ2-MSH on hypothalamic blood flow autoregulation was studied in anesthetized rats at different levels of standardized arterial hypotension. Autoregulation was impaired upon i.c.v. administration of 5 γ g/kg γ2-MSH while α-MSH caused no change.. Since this effect of γ2-MSH wa identical to that produced by i.c.v. naloxone in the same model, γ2-MSH may be a functional antagonist of central opioid mechanisms participating in the control of cerebral blood flow autoregulation.