Dose- and time-dependent cardiovascular responses induced by ethanol.

Four groups of male Sprague-Dawley rats (10/group) were instrumented to permit access to venous and arterial blood and comprehensive cardiovascular measurements for 4 h after intragastric administrations of water or 2, 4 or 6 g/kg of ethanol. Maximum blood concentrations for each increasing dose occurred within 45 min after ethanol attaining peaks of 63 +/- 8, 103 +/- 11 and 221 +/- 33 mg/d, respectively. Cardiac outputs were significantly lower than the control group beginning at 15 min for 4 and 6 g/kg and at 120 mins for 2 g/kg with similar effects on stroke volume for the three doses. Systemic vascular resistance and heart rate were consistently increased throughout the 4 h for the 6 g/kg group. There was a delayed mean arterial blood pressure decrease in the 6 g/kg group beginning at 120 min after ethanol with significant effects in the 4 g/kg group at 60 and 120 min. Decreased central venous pressure and respiration rate prevailed during the 4 h after 6 g/kg. Blood glucose concentrations were elevated at 60 min after 6 g/kg and at 240 min for all doses. However, blood temperatures were consistently lower than the control group after all three doses beginning 45 min after the drug. These data demonstrate that ethanol evokes cardiovascular, respiratory and metabolic changes that are both dose- and time-dependent. Cardiac output and systemic vascular resistance are significantly affected suggesting a marked alteration of peripheral blood flow.