Rat blood pressure during ethanol withdrawal

Abstract

Hypertension appears to be a clinical sign of ethanol withdrawal. In an effort to see if hypertension is a general consequence of ethanol withdrawal, we have monitored blood pressure and heart rate in conscious rats during ethanol withdrawal. Sprague Dawley rats were placed in Plexiglas chambers and exposed for 3 weeks to either ethanol vapor in air or to air alone. Blood ethanol levels in the ethanol treated group averaged 178±9 mg/dl during the last 2 weeks of ethanol exposure. Four to 18 hours prior to blood pressure measurement, rats were removed from the ethanol chambers, briefly anesthetized with halothane and implanted with an indwelling abdominal aortic cannula. Rats were either returned to the Plexiglas chambers and re-exposed to ethanol or air overnight or withdrawn from ethanol. Blood pressure and heart rate were then monitored at various periods from 5 hours to 4 days following the cessation of ethanol exposure. Analysis of variance revealed a significant decrease in blood pressure and heart rate in rats exposed to ethanol vapor as compared to controls. There was a significant negative correlation between the average blood ethanol levels, taken during ethanol exposure, and systolic blood pressure at 5 hours, 2 days and 3 days following cessation of ethanol exposure. These signs of hypotension and bradycardia indicate that hypertension is not a consequence of ethanol withdrawal in all animals.