Antihypoxic properties of endorphins, enkephalins and their analogs

The models of hypoxic hypoxia have been created in the experiments on mice by two ways: placing them into hermetic chamber or "lifting" them to 10.500-10.700 metres in the altitude chamber. The influence of enkephalins and their 12 analogs on the resistance of mice to hypoxia was tested. Enkephalin analogs with antihypoxic activities were detected using both models. It was shown that the mechanism of antihypoxic influence of opioids involves stimulation of their mu- and sigma-receptors and that other neurochemical systems of the body also take part in the realization of antihypoxic effects of the peptides. It is suggested that leu-enkephalin and des-tyr1-gamma-endorphin play, most likely, a role of endogenous antihypoxic agents.