title: Effect of nordihydroguaiaretic acid on intracellular Ca(2+) concentrations in C6 glioma cells.
abstract: The effect of nordihydroguaiaretic acid (NDGA) on Ca(2+) signaling in C6 glioma cells has been investigated. NDGA (5-100 microM) increased [Ca(2+)]i concentration-dependently. The [Ca(2+)]i increase comprised an initial rise and an elevated phase over a time period of 4 min. Removal of extracellular Ca(2+) reduced NDGA-induced [Ca(2+)]i signals by 52+/-2%. After incubation of cells with NDGA in Ca(2+)-free medium for 4 min, addition of 3 mM CaCl2 induced a concentration-dependent increase in [Ca(2+)]i. NDGA (100 microM)-induced [Ca(2+)]i increases in Ca(2+)-containing medium was not changed by pretreatment with 10 microM nifedipine or verapamil. In Ca(2+)-free medium, pretreatment with the endoplasmic reticulum Ca(2+) pump inhibitor thapsigargin (1 microM) abolished 100 microM NDGA-induced [Ca(2+)]i increases. Inhibition of phospholipase C with 2 microM U73122 had little effect on 100 microM NDGA-induced Ca(2+) release. Several other lipoxygenase inhibitors had no effect on basal [Ca(2+)]i. Collectively, the results suggest that NDGA increased [Ca(2+)]i in glioma cells in a lipoxygenase-independent manner, by releasing Ca(2+) from the endoplasmic reticulum in a manner independent of phospholipase C activity and by causing Ca(2+) influx.
authors.affiliation: Department of Pediatrics, Pao-Chien General Hospital, Ping Tung, Taiwan.
authors.forename: Warren
authors.initials: W
authors.lastname: Su
authors.forename: Li-Ling
authors.initials: LL
authors.lastname: Tseng
authors.forename: Muh-Chiou
authors.initials: MC
authors.lastname: Lin
authors.forename: Hsin-Ju
authors.initials: HJ
authors.lastname: Chang
authors.forename: Kam-Chung
authors.initials: KC
authors.lastname: Lee
authors.forename: Kang-Ju
authors.initials: KJ
authors.lastname: Chou
authors.forename: Yuk-Keung
authors.initials: YK
authors.lastname: Lo
authors.forename: Jin-Shiung
authors.initials: JS
authors.lastname: Cheng
authors.forename: Hong-Tai
authors.initials: HT
authors.lastname: Chang
authors.forename: Jue-Long
authors.initials: JL
authors.lastname: Wang
authors.forename: Chun-Peng
authors.initials: CP
authors.lastname: Liu
authors.forename: Wei-Chung
authors.initials: WC
authors.lastname: Chen
authors.forename: Chung-Ren
authors.initials: CR
authors.lastname: Jan
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005110:Extracellular Space / Q000378:metabolism; D005910:Glioma / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism*; D008084:Lipoxygenase / Q000502:physiology; D009637:Masoprocol / Q000494:pharmacology*; D009994:Osmolar Concentration; D014407:Tumor Cells, Cultured; D010738:Type C Phospholipases / Q000502:physiology
chemical_list: D009637:Masoprocol; D008084:Lipoxygenase; D010738:Type C Phospholipases; D002118:Calcium