Preventive effect of alcohol against stress-induced alteration in content of monoamines in brain and adrenal gland.

The possible preventive effect of alcohol on stress-induced functional changes in the brain was examined by measuring alterations in the content of monoamines, such as noradrenaline, adrenaline and 5-hydroxytryptamine, induced by the stress of immobilization in water. Application of the stress to rats for 3 hr was found to cause a significant reduction in the content of noradrenaline and 5-hydroxytryptamine in the striatum and hypothalamus, without affecting that in other central structures, in addition to the induction of a profound decrement in the content of noradrenaline and adrenaline in the adrenal gland. These alterations in the two cerebral regions were restored to the normal value at 21 hr after the application of the stress, while those found in the adrenal gland still persisted. Simultaneous administration of ethanol (2 g/kg, p.o.) almost completely prevented stress-induced alterations in the content of monoamines in the brain, but not in the adrenal gland. The administration of a larger dose of ethanol (3 g/kg, p.o.) was, however, found to exert a preventive action against the stress-induced deterioration in the content of noradrenaline and adrenaline in this endocrine organ. These results suggest that alcohol may indeed have an intimate relationship with stress in terms of prevention against the stress-induced changes in cerebral monoamines. Differential sensitivity to alcohol of the stress-induced alterations in cerebral and adrenal catecholamines is also suggested.