title: 2-O-methyl PAF as a Ca2+ mobilizer in Madin Darby canine kidney cells.
abstract: In Madin-Darby canine kidney (MDCK) cells, the effect of 2-O-methyl PAF, an inactive analogue of platelet activating factor (PAF), on intracellular Ca2+ concentration ([Ca2+]i) was measured by using the Ca2+-sensitive fluorescent dye fura-2. 2-O-methyl PAF (> or = 15 microM) caused a rapid rise of [Ca2+]i in a concentration-dependent manner. 2-O-methyl PAF-induced [Ca2+]i rise was partly reduced by removal of extracellular Ca2+. 2-O-methyl PAF-induced extracellular Ca2+ influx was also suggested by Mn2+ influx-induced fura-2 fluorescence quench. The 2-O-methyl PAF-induced Ca2+ influx was blocked by nifedipine, verapamil and diltiazem. In Ca2+-free medium, thapsigargin, an inhibitor of the endoplasmic reticulum Ca2+-ATPase, caused a monophasic [Ca2+]i rise, after which 2-O-methyl PAF failed to increase [Ca2+]i; also, pretreatment with 2-O-methyl PAF depleted thapsigargin-sensitive Ca2+ stores. U73122, an inhibitor of phospholipase C, abolished ATP (but not 2-O-methyl PAF)-induced [Ca2+]i rise. These findings suggest that 2-O-methyl PAF evokes a rapid increase in [Ca2+]i in renal tubular cells by stimulating both extracellular Ca2+ influx and intracellular Ca2+ release.
authors.affiliation: Department of Pathology and Laboratory Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan 813.
authors.forename: Jeng-Hsien
authors.initials: JH
authors.lastname: Yeh
authors.forename: Chun-Jen
authors.initials: CJ
authors.lastname: Huang
authors.forename: Jang-Hwa
authors.initials: JH
authors.lastname: Lee
authors.forename: Shu-Shong
authors.initials: SS
authors.lastname: Hsu
authors.forename: Jin-Shyr
authors.initials: JS
authors.lastname: Chen
authors.forename: He-Hsiung
authors.initials: HH
authors.lastname: Cheng
authors.forename: Hong-Tai
authors.initials: HT
authors.lastname: Chang
authors.forename: Jong-Khing
authors.initials: JK
authors.lastname: Huang
authors.forename: Hsiao-Min
authors.initials: HM
authors.lastname: Chung
authors.forename: Yeh
authors.initials: Y
authors.lastname: Mei-Yin
authors.forename: Chung-Ren
authors.initials: CR
authors.lastname: Jan
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D004285:Dogs; D005456:Fluorescent Dyes / Q000378:metabolism; D016257:Fura-2 / Q000378:metabolism; D007668:Kidney / Q000166:cytology / Q000378:metabolism*; D010972:Platelet Activating Factor / Q000031:analogs & derivatives* / Q000378:metabolism*; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D005456:Fluorescent Dyes; D010972:Platelet Activating Factor; D010738:Type C Phospholipases; D002118:Calcium; D016257:Fura-2