Abstract: | The experiments have been performed on 164 rats and 110 mice. Met-enkephalin and beta-endorphin concentration was established to increase in the blood in the early period after acute blood loss in rats who survived after 24 hours of a follow up in the group of animals, who died during 24 hours follow up, the momentary beta-endorphin increase was noted at the 1st minute of the experiment; met-enkephalin contents in blood wasn't essentially changed. mu-Receptors' agonist DAGO injection significantly decreased rat mortality in a posthemorrhagic period. The correlation between arterial pressure values and beta-endorphin and met-enkephalin contents in the blood wasn't defined. The opioid peptides' ability to increase the organism stability to hypoxia was determined. Beta-endorphin and met-enkephalin significance in the pathogenesis of a posthemorrhagic period in acute blood loss is being discussed. |