title: Effect of nortriptyline on intracellular Ca2+ handling and viability in canine renal tubular cells.
abstract: In Madin-Darby canine kidney (MDCK) cells, the effect of nortriptyline, an antidepressant, on intracellular Ca2+ concentration ([Ca2+]i) was measured by using fura-2. Nortriptyline (> 10 microM) caused a rapid increase of [Ca2+]i in a concentration-dependent manner (EC50 = 75 microM). Nortriptyline-induced [Ca2+]i increase was prevented by 40% by removal of extracellular Ca2+ but was not altered by voltage-gated Ca2+ channel blockers. In Ca(2+)-free medium, thapsigargin, an inhibitor of the endoplasmic reticulum Ca(2+)-ATPase, caused a monophasic [Ca2+]i, increase, after which the increasing effect of nortriptyline on [Ca2+], was abolished; also, pretreatment with nortriptyline reduced a large portion of thapsigargin-induced [Ca2+]i increase. U73122, an inhibitor of phospholipase C, abolished ATP (but not nortriptyline)-induced [Ca2+]i increase. Overnight incubation with 10 microM nortriptyline decreased cell viability by 16%, and 50 microM nortriptyline killed all cells. Prechelation of cytosolic Ca2+ with BAPTA did not alter nortriptyline-induced cell death. These findings suggest that nortriptyline rapidly increased [Ca2+]i in renal tubular cells by stimulating both extracellular Ca2+ influx and intracellular Ca2+ release, and was cytotoxic at higher concentrations in a Ca(2+)-dissociated manner.
authors.affiliation: Section of Allergy, Immunology and Rheumatology Chi-Mei Medical Center, Tainan 710, ROC.
authors.forename: He-Hsiung
authors.initials: HH
authors.lastname: Cheng
authors.forename: Chun-Jen
authors.initials: CJ
authors.lastname: Huang
authors.forename: Wei-Chuan
authors.initials: WC
authors.lastname: Chen
authors.forename: I-Shu
authors.initials: IS
authors.lastname: Chen
authors.forename: Shiuh-Inn
authors.initials: SI
authors.lastname: Liu
authors.forename: Shu-Shong
authors.initials: SS
authors.lastname: Hsu
authors.forename: Hong-Tai
authors.initials: HT
authors.lastname: Chang
authors.forename: Jong-Khing
authors.initials: JK
authors.lastname: Wang
authors.forename: Yih-Chau
authors.initials: YC
authors.lastname: Lu
authors.forename: Chung-Ren
authors.initials: CR
authors.lastname: Jan
mesh_terms: D000818:Animals; D000929:Antidepressive Agents, Tricyclic / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects*; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004285:Dogs; D016257:Fura-2; D042541:Intracellular Space / Q000378:metabolism; D007684:Kidney Tubules / Q000187:drug effects*; D009661:Nortriptyline / Q000494:pharmacology*; D013997:Time Factors; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: D000929:Antidepressive Agents, Tricyclic; D002121:Calcium Channel Blockers; D009661:Nortriptyline; D010738:Type C Phospholipases; D002118:Calcium; D016257:Fura-2