LIGANDS OF PURINERGIC RECEPTORS STIMULATE ELECTROGENIC H-TRANSPORT OFNEUTROPHILS()

The possible role of ATP, acting as a ligand on cell surface receptor was investigated in the activation of the electrogenic H+-transporting pathway of porcine neutrophil granulocytes. (1) ATP brought about 2.1 -fold increase in the rate of H+-efflux. (2) The order of potency of d ifferent nucleotides suggests, that ATP acts on P-2 type purinoceptor. (3) The effect of the nucleotides was prevented by inhibition of phos pholipase A(2). (4) Inhibition of the metabolism of arachidonic acid ( AA) via the cyclooxygenase pathway had no effect, whereas inhibition o f the lipoxygenase pathway significantly enhanced H+-release, This is the first report about activation of the H+-transporter by physiologic al stimulator acting on the cell surface.