Structural-metabolic changes in histaminergic neurons of the rat hypothalamus in conditions of loss of bile.

The aim of the present work was to evaluate structural and metabolic changes in histaminergic neurons in hypothalamic nucleus E2 in rats in conditions of complete external drainage of bile. Studies were performed on male Wistar rats (n = 45). Controls consisted of animals subjected to sham surgery with preservation of physiological bile flow throughout the experiment. Quantitative histological and histochemical methods were used. Serial frontal cryostat sections cut from the posterior hypothalamus were used for detection of the activity of the following enzymes: monoamine oxidase B, succinate dehydrogenase, NADH dehydrogenase, NADPH dehydrogenase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase, and acid phosphatase. Morphological studies of histaminergic neurons were performed on preparations stained with thionine. These studies showed that complete external drainage of bile led to transient size reductions and rounding of cell perikarya. Metabolic changes were seen within a day of bile loss and subsequently progressed. All energy metabolic pathways were suppressed and acid phosphatase activity was increased on day 5.