Role of intracellular calcium stores in cell death from oxygen-glucose deprivation in a neuronal cell line.
To determine the role of calcium homeostasis in ischemic neuronal death, the authors used an in vitro model of oxygen-glucose deprivation in neuronal cell lines. Exposure of human neuroblastoma SH-SY5Y cells to 10-to 16-hour oxygen-glucose deprivation decreased viability to 50% or less, and longer exposure times killed almost all cells. The death following 10-to 16-hour oxygen-glucose deprivation was not manifested until 24 to 72 hours after exposure. Deprivation of both glucose and oxygen together was required for expression of toxicity at these exposure times. Dantrolene, which blocks the release of endoplasmic reticulum Ca2+ stores, partially protected SH-SY5Y cells from oxygen-glucose deprivation toxicity. The addition of dantrolene during the deprivation phase alone produced the maximal drug effect; no further protection was obtained by continued drug exposure during the recovery phase. Prevention of Ca2+ influx by chelation or channel blockade or the chelation of cytosolic Ca2+ did not inhibit oxygen-glucose deprivation toxicity. In contrast, increasing extracellular Ca2+ or stimulating Ca2+ influx did inhibit toxicity. Calcium measurements with fura-2 acetoxymethylester revealed that oxygen-glucose deprivation caused a significant reduction in thapsigargin-releasable endoplasmic reticular stores of Ca2+. These studies suggest that an important component of the neuronal toxicity in cerebral ischemia is due to disruption of calcium homeostasis, particularly to the depletion of intracellular Ca2+ stores.
Wang
Chen
C
Department of Pharmacology, George Washington University Medical Center, Washington, District of Columbia 20037, USA.
Nguyen
Henry N
HN
Maguire
Jamie L
JL
Perry
David C
DC
D002118:Calcium / Q000378:metabolism*; D016923:Cell Death / Q000502:physiology; D003620:Dantrolene / Q000494:pharmacology; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D005947:Glucose / Q000172:deficiency / Q000502:physiology*; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010100:Oxygen / Q000502:physiology*; D019284:Thapsigargin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D019284:Thapsigargin; D003620:Dantrolene; D005947:Glucose; D010100:Oxygen; D002118:Calcium