Norepinephrine-induced diuresis in chronically ethanol-treated rats

Previous research from this laboratory indicated that noradrenergic mechanisms might mediate ethanol diuresis. Experiments described here examined changes in sensitivity of noradrenergic mechanisms in animals chronically treated with ethanol. Norepinephrine hydrochloride (0-12 micrograms intracerebroventricularly) produced dose-dependent diuresis in control (dextrin maltose) and ethanol (8-11 g/kg/day) treated rats on the first day of treatment. Tolerance to ethanol diuresis was present after 10 days of ethanol treatment. Lack of responsiveness to norepinephrine-induced diuresis was evident only on the 20th day of treatment in both the ethanol and dextrin-maltose groups of rats. These results indicate a temporal dissociation between the tolerance to ethanol-induced and norepinephrine-induced diuresis and suggest that norepinephrine may not play a primary role in the development of tolerance to the diuretic action of ethanol.