[ATRIAL AND BRAIN NATRIURETIC PEPTIDES OF CARDIAC MUSCLE CELLS IN POSTREPERFUSION PERIOD IN RATS]

Accumulation and release of atrial and brain natriuretic peptides (ANP and BNP) in right atrial cardiac muscle cells has been investigated in rats after 60 minutes and 60 days after the reperfusion start. The total ischemia was simulated by the method of V. G. Korpachev. Immunocytochemical localization of peptides in cardiomyocytes was performed in ultrathin sections using polyclonal antibodies. The intensity of accumulation/excretion of ANP and BNP were analyzed by the method of counting the number of granules (A- and B-types) with immunoreactive labels in 38 x 38 mkm2 visual fields in transmission electron microscope Morgagni 268D (FEI). The results were assessed using Mann-Whitney U-test (p < 0.05). After 60 minutes and 60 days post-reperfusion period, we detected an increase in the synthesis and release of ANP and BNP. The reaction of BNP was more pronounced than ANP. This is due to the fact that ANP is the main hormone of the natriuretic peptide system involved in the regulation of blood pressure in normal conditions, while BNP is the principal regulator of pressure in cardiovascular pathology.