Structural and metabolic disturbances in brain histaminergic neurons following alcohol administration in rats

Abstract

Aim: The aim of the study was to analyze the structural and metabolic disturbances in the brain histaminergic neurons in conditions of acute and subacute alcohol intoxications. Methods: Experiments were performed on 77 male Wistar rats weighing 175 ± 23 g. Rats of the 1st group were decapitated at 1 h after administration of the single dose of ethanol (4 g/kg as 20% saline solution (0.85 NaCl), i.p.). The rats of the 2nd group were decapitated at 1 h after the last administration of 20% ethanol solution in saline at a dose of 4 g/kg/day, i.p., for 7 days. Control animals were injected by the same volume of saline. Histaminergic neurons of the hypothalamus nucleus E2 were examined by the histological, histochemical, electron microscopic and morphometric methods. Results: Acute and subacute alcohol administrations cause disturbances of the cytoplasm chromatophilia of brain histaminergic neurons, lead to rounding of their perikarya and nuclei. Under the influence of subacute alcohol intoxication, the histaminergic neurons bodies become larger. Following single and seven-day ethanol administrations the metabolic activity of those neurons decreases. It is accompanied by acceleration of processes of the brain histamine oxidative deamination, activation of anaerobic glycolysis and intensification of autophagy processes. Single administration of alcohol leads to the development of destructive and adaptive ultrastructural changes in histaminergic neurons (activation of the nuclear apparatus, disturbance of the organization of mitochondria, endoplasmic reticulum and Golgi apparatus, lysosomal hyperplasia). Subacute alcohol administration induces more severe ultrastructural disorders. Conclusion: Acute and subacute alcohol intoxications lead to morphological and functional disorders of brain histaminergic neurons, adaptive structural and metabolic changes of those neurons, some being common to single and repeated administration regimes and others being dependent on duration of exposure to alcohol.