Effects of ethanol on mechanisms for secretory and aggregatory responses of human granulocytes

Since the mechanisms for inhibitory effects of ethanol on polymorphonuclear (PMN) leukocyte function are largely unknown we studied secretory and aggregatory responses after in vitro treatment of PMN with ethanol. Oxidative metabolism (assessed by chemiluminescence, superoxide ion production and oxygen consumption) and aggregation were reduced dose-dependently in the presence of ethanol when elicited by stimuli binding to surface receptors or other structures (fMLP and ConA). Similar results were obtained with non-receptor-dependent stimuli, as NaF and the calcium ionophore A23187. In contrast, phorbol myristate acetate peak responses were not affected. FMLP induced changes in Fura-2AM fluorescence (as a probe for fast intracellular calcium concentration changes) were, however, not influenced by ethanol. Neither were membrane potential changes [assessed by di-O-C5(3) fluorescence]. Thus, it is suggested that ethanol may impair a step of the stimulus-response-coupling in PMNs distal to the initial intracellular calcium mobilization.