Endothelin-induced activation of neutrophil migration.
Migration of rabbit peritoneal neutrophils was stimulated by endothelin-1 (ET-1) up to 2.10(-8) M. Higher concentrations inhibited random migration. The stimulating effect of ET-1 was inhibited by BQ-123, a specific antagonist of the ETA receptor. A checkerboard assay showed that the stimulating effect of ET-1 on neutrophil migration was chemokinetic rather than chemotactic. Extracellular Ca2+ was required for the activating effect of ET-1. Non-selective calcium channel blockers such as econazole and La3+ strongly inhibited ET-1-activated migration but had little effect on fMLP-activated migration, underlining the importance of Ca2+ influx for ET-1-activated migration. Studies with electroporated neutrophils showed that the increase in migration was most pronounced at calcium concentrations between 100 nM and 1 microM. ET-1-activated migration of electroporated cells was completely blocked by low concentrations of calcium-channel blockers such as verapamil and nitrendipine. Migration by intact cells was inhibited by the same concentration of verapamil, but to a lesser degree; nitrendipine had little effect on migration of intact cells. This suggests that calcium derived from intracellular stores is required for migration activated by ET-1. Protein kinase C, protein tyrosine kinase, and phosphatase activity were involved in the activating effect of ET-1 on neutrophil migration. ET-1 did not induce exocytotic enzyme release, in neither the presence nor the absence of cytochalasin B.
Elferink
J G
JG
Department of Medical Biochemistry, University of Leiden, The Netherlands.
de Koster
B M
BM
D000818:Animals; D002118:Calcium / Q000502:physiology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D016232:Endothelins / Q000502:physiology*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000166:cytology*; D010749:Phosphoprotein Phosphatases / Q000502:physiology; D011494:Protein Kinases / Q000502:physiology; D011817:Rabbits
D002121:Calcium Channel Blockers; D016232:Endothelins; D009240:N-Formylmethionine Leucyl-Phenylalanine; D007770:L-Lactate Dehydrogenase; D011494:Protein Kinases; D010749:Phosphoprotein Phosphatases; D002118:Calcium