Preadaptation to nitrogen anesthesia and impairment of rats brain cortex structure during hypoxia

The attenuating effect of various variants of hypoxia on hyperbaric anesthesia in rats was studied. The most efficient turned out to be the daily 8-fold one-hour interval 6% hypoxia that decreased manifestation of the anesthesia by 60–67%. The immunocytochemical light optical microscopy showed that in the brain cortex after the 8th seance of such hypoxia the number of neurons with the strong and moderate reaction to heat shock proteins (HSP-70) increased essentially, whereas the number of neurons with the weak reaction to these proteins decreased significantly. After the first hypoxia seances the number of cells with no reaction for the nuclear protein NeuN increased, while after its 8th seance the areas of deletion of neurons appeared. It is believed that one of the main causes of an increase of resistance of the rat organism to nitrogen anesthesia after seances of the many-day interval 6% hypoxia is accumulation of HSP-70 in brain motor cortex cells. At the same time, taking into account a possible cell death and areas of deletion of neurons in cortex during the hypoxic action, it is better to use as a preadaptogen the more moderate or not too frequent hypoxia.