Stimulation of polymorphonuclear leukocytes by dicyclohexylcarbodiimide: calcium homeostasis.
The involvement of calcium in N,N'-dicyclohexylcarbodiimide (DCCD)-mediated stimulation of guinea pig neutrophils was investigated. Exposure to DCCD resulted in a fast though moderate elevation of cytosolic calcium concentration. Exchange experiments indicated that DCCD enhanced 45Ca2+ efflux without affecting uptake of the radioisotope from the medium. Plasma membranes isolated from DCCD-stimulated cells failed to support ATP-dependent 45Ca2+ uptake indicating inhibition of their Ca-ATPase. The finding that the enhanced efflux of 45Ca2+ depended on the presence of Na+ ions in the medium implicated a Na+/Ca2+ exchanger in efflux of the ion observed in DCCD-stimulated neutrophils. This is the first indication for the participation of this carrier in calcium homeostasis in stimulated neutrophils. Experiments carried out with 14C-DCCD indicated covalent binding of the reagent to 20 and 150 Kd membrane proteins.
Aviram
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Department of Biochemistry, Faculty of Life Sciences, Tel-Aviv University, Israel.
Aviram
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D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000032:analysis / Q000378:metabolism* / Q000494:pharmacology; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000502:physiology; D002234:Carbodiimides / Q000494:pharmacology*; D002462:Cell Membrane / Q000378:metabolism / Q000502:physiology; D004024:Dicyclohexylcarbodiimide / Q000378:metabolism / Q000494:pharmacology*; D005089:Exocytosis / Q000187:drug effects; D006168:Guinea Pigs; D006706:Homeostasis; D009504:Neutrophils / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D012964:Sodium / Q000494:pharmacology
D002234:Carbodiimides; D004024:Dicyclohexylcarbodiimide; D000255:Adenosine Triphosphate; D012964:Sodium; D000252:Calcium-Transporting ATPases; D002118:Calcium