Influence of ethanol on histamine metabolism and release in the rat brain. II. Regions of the histaminergic pathway.

Following acute alcohol administration (80-160 mg/100 g body weight) histamine levels of rat brain cortex and thalamus were elevated and histidine decarboxylase activity was decreased. The effect was less pronounced after chronic alcohol treatment (15% v/v in drinking water for 4 weeks). In the striatum there was no change in the metabolic pattern of histamine. Histamine-N-methyltransferase was unaffected in either case. Depolarisation-induced release of histamine was inhibited by alcohol in the hypothalamus, thalamus and cortex. The results indicate that ethanol affects the histamine metabolism and release processes in the histaminergic pathway of the brain.