A vasoactive serum component and reactivity of isolated rat aorta after chronic alcohol administration

Norepinephrine-induced contractility and relaxation to acetylcholine of isolated aortas taken from normal and chronic alcoholic rats were measured. Similar experiments were performed adding serum from normal (NS) or alcoholic rats (AS), with or without norepinephrine and acetylcholine. Responses of normal and alcoholic aortas to agonists were comparable. NS and AS induced contractions on normal aorta, but the responses of alcoholic aortas were lower; contractions induced by AS on both aortas were larger than those induced by NS. AS decreased verapamil-induced relaxation more than NS. A pressor circulating factor might be responsible.