Influence of intravenous infusion of ethanol on regional blood flow in conscious rats.

The effects of intravenous infusions of ethanol and saline (0.9% NaCl) on mean arterial pressure (MAP), heart rate (HR), total peripheral resistance (TPR), cardiac contractility (dP/dtmax) and systemic haemodynamics were studied in conscious, unrestrained rats by the radioactive microsphere technique. Saline (0.03 and 0.06 mL min-1 kg-1 for 12 min each dose) in the time-control group did not affect MAP, HR, TPR, dP/dtmax or vascular conductances in any organs or beds. While the low dose ethanol (2.4 mg min-1 kg-1) did not alter MAP, HR, TPR, systemic haemodynamics or dP/dtmax, the high dose (4.8 mg min-1 kg-1) slightly reduced MAP and TPR but did not affect HR, cardiac output or dP/dtmax. Both doses of ethanol vasodilated the intestine and spleen, but vasoconstricted the skin. The high dose caused additional vasodilatation in the heart and testes and the low dose also constricted the skeletal muscle bed. Our results show that ethanol, at non-hypotensive or slightly hypotensive doses, has marked vasodilator effects in the heart, intestine, spleen and testes.