title: Effect of riluzole on Ca2+ movement and cytotoxicity in Madin-Darby canine kidney cells.
abstract: Riluzole is a drug used in the treatment of amyotrophic lateral sclerosis; however, its in vitro action is unclear. In this study, the effect of riluzole on intracellular Ca2+ concentration ([Ca2+]i) in Madin-Darby canine kidney (MDCK) cells was investigated using the Ca2+ -sensitive fluorescent dye, fura-2. Riluzole (100-500 microM) caused a rapid and sustained increase of [Ca2+]i in a concentration-dependent manner (EC50 = 150 microM). Some 40 and 50% of this [Ca2+]i increase was prevented by the removal of extracellular Ca2+ and the addition of La3+, respectively, but was unchanged by dihydropyridines, verapamil and diltiazem. In Ca2+ -free medium, thapsigargin - an inhibitor of the endoplasmic reticulum (ER) Caz+ -ATPase--caused a monophasic [Ca2+]i increase, after which the increasing effect of riluzole on [Ca2+]i was attenuated by 70%; in addition, pre-treatment with riluzole abolished thapsigargin-induced [Ca2+]i increases. U73122, an inhibitor of phospholipase C (PLC), abolished ATP (but not riluzole)-induced [Ca2+]i increases. At concentrations of 250 and 500 microM, riluzole killed 40 and 95% cells, respectively. The cytotoxic effect of riluzole (250 microM) was unaltered by pre-chelating cytosolic Ca2+ with BAPTA. Collectively, in MDCK cells, riluzole rapidly increased [Ca2+]i by stimulating extracellular Ca2+ influx via an La3+ -sensitive pathway and intracellular Ca2+ release from the ER via, as yet, unidentified mechanisms. Furthermore, riluzole caused Ca2+ -unrelated cytotoxicity in a concentration-dependent manner.
authors.affiliation: Department of Surgery, Ping Tung Christian Hospital, Ping Tung, Taiwan.
authors.forename: W C
authors.initials: WC
authors.lastname: Chen
authors.forename: H H
authors.initials: HH
authors.lastname: Cheng
authors.forename: C J
authors.initials: CJ
authors.lastname: Huang
authors.forename: C T
authors.initials: CT
authors.lastname: Chou
authors.forename: S I
authors.initials: SI
authors.lastname: Liu
authors.forename: I S
authors.initials: IS
authors.lastname: Chen
authors.forename: S S
authors.initials: SS
authors.lastname: Hsu
authors.forename: H T
authors.initials: HT
authors.lastname: Chang
authors.forename: J K
authors.initials: JK
authors.lastname: Huang
authors.forename: C R
authors.initials: CR
authors.lastname: Jan
mesh_terms: D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002491:Central Nervous System Agents / Q000494:pharmacology*; D004285:Dogs; D007668:Kidney / Q000166:cytology; D019782:Riluzole / Q000494:pharmacology*
chemical_list: D002491:Central Nervous System Agents; D019782:Riluzole