Reduction of Striatal Dopamine Release during an Ethanol Withdrawal Syndrome.

摘要

In an attempt to assess dopaminergic activity by a different experimental approach, the present investigation explores the measurement of dopamine release in vitro in the caudate nucleus of the rats as a function of acute and chronic administration of ethanol. Male Sprague-Dawley rats were treated with a single dose of ethanol or rendered ethanol-dependent by the method of Majchrowicz (1975). A single dose of ethanol accelerated K(+) -stimulated dopamine release in a dose-dependent manner until blood ethanol concentrations reached about 300 mg/dl. Above this amount dopamine release progressively declined until K(+) was incapable of stimulating release. If animals were rendered ethanol-dependent, dopamine release was elevated when they were still intoxicated. However, 6-8 hours later when a fully developed withdrawal syndrome had developed, dopamine release was inhibited. The results observed after acute and chronic treatment with ethanol do not appear to be due to a direct effect since ethanol added to the incubation medium in physiologically compatible concentrations had no effect on dopamine release and no ethanol was present in striata of treated animals at the time the high K(+) concentrations were added.