[Effects of changes in mitochondrial permeability transition of medullary neurons on arterial pressure in rats]

In acute experiments on anaesthetized with urethane normotensive rats we studied effects of modulating the mitochondrial permeability transition (MPT) of the neurons in the medullary cardiovascular nuclei - nucleus of the tractus solitarius (NTS), paramedian reticular nucleus (PMn), n.ambiguus (AMB), and lateral reticular nucleus (LRN) on the systemic arterial pressure level (SAP). An increase in the MPT with injections of an inductor for MPT phenylarsine oxide (10(-12) M - 10(-8) M) into the medullary nuclei under exploration has been shown to induce the lowering in the SAP level in a dose-dependent manner. A decrease in the MPT of the medullary neurons with either cyclosporine A or melatonin (10(-12) M - 10(-10) M) resulted in hypertensive responses of the SAP. Effects of phenylarsine oxide injections into the medullary nuclei were attenuated after preliminary intravenous administration of L-arginine. The data obtained give evidence that functional activity of the medullary cardiovascular neurons and their effects depend to a large extent on the functional state of their mitochondria.