The mechanism of enhancement of the neurogenic oedema response by baclofen.

The effect of baclofen on the neurogenic oedema response to electrical stimulation of the saphenous nerve in rats was investigated. Baclofen 2.5 x 10(-6) mol given intravenously enhanced the neurogenic oedema response and increased blood pressure. The enhancement was not specific to the neurogenic oedema response since plasma exudation responses to substance P, histamine and 5-hydroxytryptamine were also enhanced. No local interactions between baclofen and agents inducing plasma exudation were found which would account for this effect of baclofen. Since agents which abolished the pressor response to baclofen (alpha and beta-adrenoceptor antagonists, hexamethonium, reserpine) also abolished the enhancement of neurogenic oedema, it was concluded that baclofen enhanced the response by its action on the cardiovascular system.