title: Collagen-stimulated superoxide production: evidence for coupled mobilization of calcium.
abstract: Superoxide production by human neutrophils was stimulated by rat liver collagen. The stimulation was exponentially related to the collagen concentration, with maximal effect at 150 micrograms/ml. The collagen-induced effect was significantly enhanced by the presence of Ca2+ in the medium. Verapamil--a calcium channel blocker--caused a dose-dependent inhibition of superoxide production by collagen-stimulated neutrophils. Collagen-induced stimulation was associated with a transient rise in cytosolic free Ca2+ independent of the presence of Ca2+ in the medium. Depletion of intracellular calcium caused a significant decrease in superoxide activity; however, replenishment of Ca2+ in the medium significantly overcame the inhibition. These changes were associated with a direct binding of [14C]collagen with the neutrophils. Our data suggest that collagen-neutrophil interaction couples superoxide production with the process of Ca2+ mobilization and that this interaction may play a physiologic role in neutrophil stimulation.
authors.affiliation: Department of Experimental Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: K I
authors.initials: KI
authors.lastname: Andrabi
authors.forename: N
authors.initials: N
authors.lastname: Kaul
authors.forename: S
authors.initials: S
authors.lastname: Mudassar
authors.forename: J B
authors.initials: JB
authors.lastname: Dilawari
authors.forename: N K
authors.initials: NK
authors.lastname: Ganguly
mesh_terms: D000818:Animals; D002118:Calcium / Q000097:blood*; D002413:Cations, Divalent; D003094:Collagen / Q000097:blood / Q000302:isolation & purification / Q000494:pharmacology*; D003600:Cytosol / Q000378:metabolism; D004533:Egtazic Acid / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008099:Liver / Q000737:chemistry; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D011489:Protein Denaturation; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000378:metabolism; D038981:Receptors, Collagen; D013481:Superoxides / Q000097:blood*; D014700:Verapamil / Q000494:pharmacology
chemical_list: D002413:Cations, Divalent; D011956:Receptors, Cell Surface; D038981:Receptors, Collagen; D013481:Superoxides; D004533:Egtazic Acid; D003094:Collagen; D014700:Verapamil; D002118:Calcium