Regional brain acetylcholine levels in rats acutely treated with ethanol or rendered ethanol-dependent

Abstract

Abstract : A study of brain acetylcholine (ACh) levels was undertaken in an attempt to reconcile discrepancies reported on the effects of ethanol treatment on the cholinergic system. ACh levels were measured in six areas of brains of male Sprague-Dawley rats after a single dose of ethanol or after the induction of ethanol dependence. At various times after treatment the rats were euthanatized by focused microwave irradiation. The excised brains were dissected into the following parts: cerebellum, brain stem, hypothalamus, hippocampus, caudate nucleus and cerebral cortex. After an acute dose of ethanol, ACh levels increased in most areas of the brain when blood ethanol concentrations were quite high. As blood ethanol declined, ACh levels decreased to below control values with similar results observed in ethanol-dependent rats still intoxicated. No significant changes in ACh levels were observed in ethanol-dependent rats undergoing a withdrawal syndrome. These data suggest that ethanol treatment exerts multiple effects on the cholinergic system, but they do not as yet support a role of ACh in the expression of the ethanol withdrawal syndrome. The results of this study provide further information on the development and exploration of models for chronic insults to the brain, such as long-term exposure to toxic chemicals and ionizing and nonionizing radiation. (Author)