Radchenko N. The features of GABA-ergic medullary cardiovascular control in rats.

The study is devoted to examining the features of GABA-ergic cardiovascular control in rats. It has been shown that an inhibitory GABA-ergic control is realized through specific GABAA-receptors on the medullary neurons. After the suppression of neuronal NO-synthase by a specific antagonist 7 nitroindazole, GABA injections in the investigated nuclei of the medulla oblongata are accompanied by weakening of the hypotensive responses, which indicates the interaction between GABA and NO in the inhibitory GABA-ergic cardiovascular control. The priority data have been obtained that membrane enzyme, Na+, K+-ATPase is involved in the medullary cardiovascular control in rats in the norm and in hypertension, and the level of the enzyme is much higher in the medulla oblongata of spontaneously hypertensive rats, than in the norm. The contribution of Na+, K+-ATPase to the inhibitory GABA-ergic cardiovascular control has been suggested, as GABA-induced effects on the hemodynamics were attenuated following blockade of that enzyme. We have evaluated the possibility of single-walled carbon nanotubes (SWNTs) to influence the cardiovascular system through modulating activity of the medullary cardiovascular neurons. For the first time it has been shown that injections of SWNTs in the medullary nuclei of both normotensive and spontaneously hypertensive rats result in the hypotensive responses which are more pronounced in hypertensive rats. It has been found that the SWNTs in the concentration used did not significantly affect the hypotensive responses, but they attenuated GABA-induced hypertensive ones.