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Effect of Riluzole on Ca2+ Movement and Cytotoxicity in Madin-Darby Canine Kidney CellsDepartment of Surgery, Ping Tung Christian Hospital, Ping Tung, Taiwan 900
Section of Allergy, Immunology and Rheumatology, Chi-Mei Medical Center, Tainan, Taiwan 710
Department of Psychiatry, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan 807, Department of Psychiatry, Tian-Sheng Memorial Hospital, Ping-Tong, Taiwan 900
Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan 813
Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan 813
Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan 813
Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan 813
Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan 813
Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan 813
Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan 813, crjan{at}isca.vghks.gov.tw 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 mM) caused a rapid and sustained increase of [Ca2 -]i in a concentration-dependent manner (EC50 = 150 mM). 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) Ca2 --ATPase -caused a monophasic [Ca2-]i increase, after which the increasing effect of riluzole on [Ca2 -]iwas 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 mM, riluzole killed 40 and 95% cells, respectively. The cytotoxic effect of riluzole (250 mM) was unaltered by pre-chelating cytosolic Ca2 - with BAPTA. Collectively, in MDCK cells, riluzole rapidly increased [Ca2 -]i by stimulating extra-cellular 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-depen-dent manner.
Key Words: Ca2+ Ca2+ stores fura-2 Madin-Darby canine kidney renal tubular cells riluzole
Human & Experimental Toxicology, Vol. 25, No. 8,
461-469 (2006) |
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