title: Extra- and intracellular Ca2+ requirements for lysosomal enzyme secretion in human neutrophils.
abstract: Ca2+-EGTA combinations were utilized in Hank's buffers to fix extracellular free Ca2+ concentrations [Ca2+f] for the study of human neutrophil lysosomal enzyme secretion. Ca2+-dependent neutrophil secretion initiated by formyl-methionyl-leucyl-phenylalanine (FMLP) and C5a required small amounts of [Ca2+f] (1-3 x 10(-6) M) while that caused by ionophore A23187 required 10(-5) M or greater [Ca2+f]. The inhibition of FMLP- and C5a-induced lysosomal enzyme secretion by the intracellular Ca2+ antagonist, 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8) was additive to lowering extracellular [Ca2+f] from 10(-4) M to 10(-6) M or blocking plasma membrane Ca2+ flux with verapamil. These results suggest that extracellular and intracellular Ca2+ flux may be coupled in the initiation of neutrophil secretion caused by FMLP and C5a.
mesh_terms: D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000502:physiology*; D003182:Complement C5; D015936:Complement C5a; D003571:Cytochalasin B / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D005707:Gallic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D005966:Glucuronidase / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008247:Lysosomes / Q000201:enzymology*; D009239:N-Formylmethionine / Q000031:analogs & derivatives / Q000494:pharmacology; D009240:N-Formylmethionine Leucyl-Phenylalanine; D009504:Neutrophils / Q000201:enzymology*; D009842:Oligopeptides / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
chemical_list: D003182:Complement C5; D009842:Oligopeptides; D000001:Calcimycin; D003571:Cytochalasin B; D009239:N-Formylmethionine; D004533:Egtazic Acid; C006014:8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate; D009240:N-Formylmethionine Leucyl-Phenylalanine; D005707:Gallic Acid; D015936:Complement C5a; D014700:Verapamil; D005966:Glucuronidase; D002118:Calcium