The effect of alcohol inhalation on the cardiovascular state of the rat.

Rats were exposed to alcohol vapors by an inhalation technique and blood pressure and its reactivity and platelet aggregation were measured. Acute exposure to alcohol levels which produced moderate blood alcohol concentration (BAC) was associated with increased vascular production of prostacyclin (PGI2) and plasma catecholamines, whereas platelet production of thromboxane (TXA2) decreased. Blood pressure is elevated in these animals, however, the platelet aggregating and pressor effects of noradrenaline (NE) were decreased. Chronic exposure to high BAC is associated with a dramatic reduction in vascular and platelet prostaglandin (PG) production and a marked increase in plasma catecholamine levels. Platelet aggregation decreased in these animals, however, the pressor effect of TXA2 and NE was significantly increased. The fatty acid precursors to PG were reduced by 50% in the lipid extracts of these preparations. These findings suggest that alterations in fatty acid metabolism may lead to a functional deficiency in PG production from dependent rats. Qualitative differences may exist between acute and chronic exposure with respect to the cardiovascular state. Locally produced PG and circulating catecholamines may mediate alcohol-induced alterations in vascular smooth muscle tone and platelet aggregation.