Ethanol-induced changes of histamine content in guinea-pig brain.

Acute treatment of guinea-pigs with ethanol (5 g/kg, directly into the stomach) slightly (by approximately 15%) decreased histamine (HI) content in the hypothalamus, cerebral cortex, rest of the brain and in the whole brain. Prolonged treatment (7-18 days of daily alcohol administration; doses were gradually increasing from 5 to 10 g/kg daily) increased the amine level in the studied tissues by 20-40%. Prolonged treatment of the animals with ethanol plus pyridoxal (Vitamin B6) increased brain HI content to approximately the same extent as did ethanol alone. Both acute and prolonged (18 days) treatment with ethanol did not significantly change activity of the HI synthesizing enzyme, i.e. L-histidine decarboxylase, in the cerebral cortex and in the rest of the brain. The mechanism of ethanol-induced changes in brain HI content is discussed.