Plasma catecholamines in ethanol tolerance and withdrawal in mice.

Plasma levels of catecholamines (noradrenaline and adrenaline) as well as the ratio of the two catecholamines were measured in experimental mice during various stages of acute and chronic ethanol treatment. Acute intraperitoneal (i.p.) ethanol administration and acute per os (p.o.) ethanol ingestion resulted in a similar elevation of the plasma levels of both catecholamines. During the development of ethanol tolerance/dependence (ingestion of drinking water containing ethanol for 14 days), plasma catecholamine concentrations returned to the control levels. During subsequent ethanol withdrawal, a highly significant increase was observed in plasma noradrenaline. The withdrawal-associated elevation of plasma adrenaline was also significant; however, the rise in plasma noradrenaline during withdrawal appeared to be higher than that found for adrenaline. Thus, the ratio of plasma noradrenaline to adrenaline was higher during withdrawal, and this ratio also exhibited an association with the severity of ethanol withdrawal symptoms. Since plasma noradrenaline derives to a great extent from the sympathetic nervous system--and the alcohol withdrawal syndrome is characterized by symptoms of overactivity of this system--a positive correlation may exist between noradrenaline and the severity of withdrawal symptomatology.