Influence of Chronic Alcohol Consumption on Histaminergic Neurons of the Rat Brain

Aims: To clarify the effect of chronic alcohol consumption on the brain histaminergic neurons in rats. Methods: Male Wistar rats were given 20% ethanol as the only source of drinking during 6 months, control rats had a free access to water. The samples of hypothalamus were prepared for light and electron microscopy accompanied by morphometry to examine the brain histaminergic neurons of E2 group. Results: Chronic ethanol consumption increased the amount of histologically abnormal forms of histaminergic neurons and decreased the whole amount of E2 histaminergic neurons (for 5%). The neuron bodies and nuclei increased in size and sphericity, the nuclear/cytoplasmic ratio decreased by 15%. The ultrastructural changes in histaminergic neurons demonstrate the activation of their nuclear apparatus, both destruction and hypertrophy and hyperplasia of organelles, especially lysosomes. Chronic ethanol consumption induces the disturbances in cytoplasmic enzymes of neurons: increases the activity of type B monoamine oxidase, dehydrogenases of lactate and NADH and, especially, marker enzyme of lysosomes acid phosphatase as well as inhibits the activity of dehydrogenases of succinate and glucose-6-phosphate. Conclusion: Chronic alcohol consumption affects significantly the structure and metabolism of the brain histaminergic neurons, demonstrating both the neurotoxic effect of ethanol and processes of adaptation in those neurons, necessary for their survival