An increase in the activity of NADPH-dependent O 2 - -producing and ferrihemoglobin-reducing isoforms of cytochrome b 558 from membranes, mitochondria, and nuclei of cells of rats subjected to electrical stimulation of the supraoptic and paraventricular hypothalamic nuclei

Electrical stimulation of supraoptic nuclei (SON) and paraventricular nuclei (PVN) of the hypothalamus increases the immunoreactivity of the rat hypothalamus. However, molecular mechanisms of this effect associated with changes in the level of isoforms of cytochrome (cyt) b (558) in membranes, mitochondria, and nuclei of cells of rat organs (brain, liver, spleen, heart, and kidneys) are unknown. Determination of these factors was the aim of this study. The SON and PVN of the hypothalamus of white mature rats were subjected to electrical stimulation by rectangular electrical impulses. The acidic cyt b (558) from cell membranes, mitochondria, and nuclei was extracted using ion-exchange chromatography of protein fractions with KM-52 and DE-52 celluloses. The electrical stimulation of the hypothalamus in the majority of cases resulted in an increase in the level of acidic cyt b (558) in the membranes, mitochondria, and nuclei of cells of all organs studied, especially the spleen. Cytochrome b (558) along with NADPH-dependent O (2) (-) -producing activity also had methemoglobin-reducing activity. On the basis of our results, it is possible to hypothesize that the molecular mechanisms that increase the immunoreactivity of SON and PVN of the hypothalamus are associated with an increase in the endogenous level and activity of isoforms of acidic cyt b (558) from membranes, mitochondria, and nuclei of cells. These mechanisms may also involve stimulation of the immune system, oxygen homeostasis, genome regulation, and energetic balance in the respiratory chain of mitochondria.