Effects of Intravenous Acetaldehyde, Acrolein, Formaldehyde and Propionaldehyde on Arterial Blood Pressure Following Acute Guanethidine Treatment

Abstract

Guanethidine (G) is currently used in the treatment of essential hypertension. Acetaldehyde (A), acrolein (AR), formaldehyde (F) and propionaldehyde (P) are constituents of cigarette smoke and (A) is also an intermediate oxidative metabolite of ethanol. These aldehydes are known to produce sympathomimetic effects by the release of NE from adrenergic neurons and to exert cardioinhibitory effects. The type of predominant effect is dose-dependent. This study was undertaken to determine if these aldehydes result in sympathomimetic effects in the presence of G (15 mg/kg iv) in anesthetized rats. G enhanced the pressor responses to A and P in dose ranges of 5-20 and 5-10 mg/kg respectively. However, AR and F at dose ranges of 0.05-5 and 0.1-10 mg/kg, respectively, elicited only depressor responses after G. Thus, A and P exerted greater sympathomimetic effects through the release of intraneuronal NE in the presence of G. The adrenergic neuronal blocking action of G changes the blood pressure effects of AR and F. When these two compounds are administered in the absence of G, they cause predominant pressor effects, whereas in the presence of G a depressor response is noted. This depressor response is possibly by vagal stimulation and/or direct vasodilation.