title: Stimulation of Ca2+ efflux by N-formyl chemotactic peptides in guinea-pig peritoneal macrophages.
abstract: Effects of N-formyl chemotactic peptides on the Ca2+ influx and efflux were investigated in guinea-pig peritoneal macrophages using an isotope tracer. fMet-Leu-Phe did not enhance the influx of 45Ca2+ into macrophages, whereas it stimulated the efflux of 45Ca2+ from macrophages at concentrations ranging from 10(-10) M to 10(-7) M. fMet-Met-Met and fMet-Leu also stimulated the 45Ca2+ efflux, albeit at much higher concentrations, while there was no stimulation with fMet. The mitochondrial inhibitors, oligomycin and NaN3, did not modify the 45Ca2+ efflux induced by the chemoattractants, yet they did induce the release of 45Ca2+ from the mitochondria. On the other hand, higher concentrations of the calmodulin antagonists, chlorpromazine and trifluoperazine, induced the release of 45Ca2+ from the NaN3-insensitive Ca2+ store site and mimicked the enhancement of the 45Ca2+ efflux by N-formyl chemotactic peptides. Thus, N-formyl chemotactic peptides appear to increase the levels of intracellular free Ca2+ in guinea-pig peritoneal macrophages, probably by inducing the release of Ca2+ from the NaN3-insensitive Ca2+ store site.
mesh_terms: D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002630:Chemotactic Factors / Q000494:pharmacology; D002746:Chlorpromazine / Q000494:pharmacology; D006168:Guinea Pigs; D007700:Kinetics; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D002630:Chemotactic Factors; D009240:N-Formylmethionine Leucyl-Phenylalanine; D002118:Calcium; D002746:Chlorpromazine