title: Human platelet calcium measurements. Methodological considerations and comparisons with calcium mobilization in vascular smooth muscle cells.
abstract: Platelets are used as models for vascular smooth muscle cells (VSMC) in evaluating intracellular calcium ([Ca2+]i) metabolism in humans. This study was designed to determine if agonist-induced increases in [Ca2+]i in platelets occur via release from intracellular stores as previously demonstrated for VSMC. Incubation of purified platelets loaded with fura-2-AM in media containing 1.5 mmol/L Ca2+ resulted in higher basal [Ca2+]i than platelets incubated in Ca(2+)-free media. In addition, vasopressin-induced platelet [Ca2+]i transients were almost completely blocked by Ca2+ channel blockers. Thus, in contrast to VSMC, the transmembranous flux of extracellular Ca2+ is the major mechanism in vasopressin-induced increases in platelet [Ca2+]i, while mobilization of intracellular Ca2+ stores is only minimally involved.
authors.affiliation: Wayne State University School of Medicine, Detroit, Michigan 48201.
authors.forename: P R
authors.initials: PR
authors.lastname: Standley
authors.forename: S
authors.initials: S
authors.lastname: Gangasani
authors.forename: R
authors.initials: R
authors.lastname: Prakash
authors.forename: M B
authors.initials: MB
authors.lastname: Zemel
authors.forename: J R
authors.initials: JR
authors.lastname: Sowers
mesh_terms: D001127:Arginine Vasopressin / Q000494:pharmacology; D001792:Blood Platelets / Q000737:chemistry* / Q000378:metabolism; D002118:Calcium / Q000097:blood*; D016257:Fura-2 / Q000031:analogs & derivatives; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000378:metabolism
chemical_list: C049925:fura-2-am; D001127:Arginine Vasopressin; D002118:Calcium; D016257:Fura-2