FORMATION OF PLASMA-MEMBRANE SIGNAL ATP WITH ACTIVATED NEUTROPHILS AND MACROPHAGES - RELATIONSHIP BETWEEN SUPEROXIDE PRODUCTION AND THE STATE OF FORMYL-PEPTIDE RECEPTORS

Formation of plasmatic membrane signal ATR in target cells containing growth peptide factors have been found in various mammalian tissues including neutrophils activated by formyl-peptide. Maximal development of the plasmatic membrane ATP was observed within 3 days in neutrophils of rats with septicopyemia. Production of superoxide anion in neutrophils of these rats was the highest also within 3 days and constituted 3.7 nmol/mg of protein as compared with 1.4 nmol/mg in controls; within the subsequent periods dynamics of the superoxide anion content correlated with the rate of plasmatic membrane signal ATP synthesis, The state of receptors to formyl-peptide was altered as follows: content of their binding sites in neutrophils was distinctly decreased at the beginning of septicopyemia and continued to decrease within later periods but the receptors affinity was not altered. Thus, production of superoxide anion was not related directly to amount of receptors to formyl-peptide while it correlated with formation of the plasmatic membrane signal ATP. The phenomenon of the signal ATP synthesis in neutrophils occurred mainly at concentrations of formyl-peptide activating phagocytosis. Other immunocompetent cells-macrophages produced also the plasmatic membrane signal ATP, 28.1 nmol/mg of protein, after stimulation with formyl-peptide and their ATP-formating activity was the highest among the target cells studied. This suggests that plasmatic membrane signal ATP is involved in membrane transduction of a signal to activation of neutrophils and macrophages.