Inhibitors of membrane transport reduce lysosomal enzyme secretion from dogfish phagocytes and their killing of sea urchin eggs

Effects of protein I of Neisseria gonorrhoeae on neutrophil activation: generation of diacylglycerol from phosphatidylcholine via a specific phospholipase C is associated with exocytosis.

“…Between 30 and 60 s the generation of a slow, prolonged wave ofdiacylglycerol became apparent . Levels of diacylglycerol remained elevated for at least 300 s. In the presence of protein I, however, generation ofboth Effect of DIDS on Diacylglycerol Generation DIDS, an inhibitor ofthe anion transporter, has been shown, both by morphological as well as enzymatic criteria, to inhibit degranulation from neutrophils without affecting superoxide anion generation (24,32) . We therefore determined whether Effect of Protein I on Kinase C Activation Diacylglycerol is an intracellular messenger presumed to activate protein kinase C, the calcium, phospholipid-dependent protein kinase (39).…”

“…In this report we demonstrate that protein I inhibits slow DG generation after treatment of cells with FMLP but has no affect on rapid diacylglycerol . DIDS, an anion transport inhibitor that alters neutrophil functions in a manner identical to protein I (24,33) similarly inhibited DG formation after FMLP Other investigators, by specifically labeling the pool of 1-0-alkyl, 2-acyl-phosphatidylcholine in neutrophils by means of the lyso derivative of EA-PC have demonstrated that slow 1-0-alkyl, 2-acylglycerol derives from EA-PC by activity of a phospholipase D. In contrast, our studies have analyzed the pool(s) of phospholipids which have ester-linked fatty acids in both the sn-1,2 positions . To determine the source of the slow diacylglycerol, we measured radiolabeled phospholipid turnover provoked by FMLP in the presence and absence of protein I .…”

Anion blockers inhibit impulse‐evoked quantal transmitter release at the crayfish neuromuscular junction

“…For example, Probenecid, pyridoxal-5'-phosphate, and 4-acetamido-4'-isothiocyanostilbene-2,2'-disulphonate (SITS) block thrombin-evoked release of serotonin from platelets (Pollard, Tack-Goldman, Pazoles, Creutz & Shulman, 1977) and acetylcholine-evoked secretion of norepinephrine by adrenal chromaffin cells (Pollard, Pazoles, Creutz & Zinder, 1979). They also prevent lysosomal enzyme secretion from neutrophils in response to antigen-antibody complexes (Korchak, Eisenstatt, Hoffstein, Dunham & Weissman, 1980) and release of cortical granule contents by the fertilized sea urchin egg (Dunham, Arvan, Falkow, Hoffstein & Weissmann, 1979). At low concentrations of these agents, their inhibitory effects on secretion are mitigated by raising the extracellular concentration of certain anions, such as chloride or bicarbonate (Pollard, Pazoles, Creutz & Zinder, 1980).…”