Journal of Neuroscience, Vol 14, 4040-4049, Copyright © 1994 by Society for Neuroscience
Cytosolic free calcium and cell death during metabolic inhibition in a neuronal cell line
ME Johnson, GJ Gores, CB Uhl and JC Sill
Department of Anesthesiology, Mayo Foundation, Rochester, Minnesota 55905.
Elevated free cytosolic Ca2+ (Ca2+i) has been implicated as a mechanism of
hypoxic neuronal death. The calcium hypothesis postulates that the basic
metabolic response to hypoxic ATP depletion is a toxic increase in free
cytosolic Ca2+i in all cell types. This inherent response then creates the
environment in which subsequent derangements of Ca2+i may occur, for
example, from glutamate excitotoxicity. Although the effect of glutamate on
neuronal Ca2+i has been extensively studied, the basic neuronal response to
hypoxia independent of glutamate receptor activation is not well defined.
We therefore assayed both Ca2+i and plasma membrane integrity in
fura-2-loaded, single SK-N-SH neuroblastoma cells, using digitized video
microscopy and metabolic inhibition (2.5 mM NaCN, 10 mM 2-deoxyglucose) to
model the ATP depletion of hypoxia. Median time to cell death was 90 min (n
= 51 cells). Initial Ca2+i was 121 +/- 67 nM. Ca2+i increased by 50 nM
after 5-10 min of metabolic inhibition. Blebbing of the cell membrane was
evident within 30 min. Ca2+i did not appreciably increase further until the
time of cell death, when the loss of plasma membrane integrity allowed
unimpeded influx of extracellular Ca2+.(ABSTRACT TRUNCATED AT 250 WORDS)
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