title: Ca2+ ionophores inhibit superoxide generation by chemotactic peptide in rabbit neutrophils and the correlation with intracellular calcium.
abstract: Effects of Ca2+ ionophores, A23187 and lasalocid, on superoxide anion generation by chemotactic peptide, N-formyl-methionyl-leucyl-phenylalanine methyl ester, in rabbit peritoneal exudate neutrophils were studied. The ionophores by themselves did not activate superoxide anion generation in these neutrophils. When preincubated with the cells for 2 min, both the ionophores inhibited superoxide generation induced by chemotactic peptide. The inhibition was present even in the absence of extracellular Ca2+ and the inhibition was better then. Lasalocid produces a dose-dependent chlortetracycline fluorescence decrease response in neutrophils loaded with chlortetracycline. This response is independent of extracellular Ca2+ concentration and is related to release of Ca2+ from intracellular storage sites. The dose-range at which lasalocid gives this response is same as the dose-range at which it causes inhibition of superoxide response. It may be concluded that the inhibition of superoxide generation by these ionophores is correlated to intracellular Ca2+ modulation.
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore.
authors.forename: J
authors.initials: J
authors.lastname: Jacob
mesh_terms: D000818:Animals; D000001:Calcimycin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002751:Chlortetracycline; D007832:Lasalocid / Q000494:pharmacology*; D008297:Male; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000378:metabolism*; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D011817:Rabbits; D013050:Spectrometry, Fluorescence; D013481:Superoxides / Q000378:metabolism*
chemical_list: D013481:Superoxides; D000001:Calcimycin; D009240:N-Formylmethionine Leucyl-Phenylalanine; D002118:Calcium; D007832:Lasalocid; D002751:Chlortetracycline