EFFECT OF LOW-TEMPERATURE ON GLUTAMATE-INDUCED INTRACELLULAR CALCIUM ACCUMULATION AND CELL-DEATH IN CULTURED HIPPOCAMPAL-NEURONS

To elucidate the precise mechanism of neuronal protection by brain hyp othermia, we conducted an investigation as to what effect low temperat ure had on glutamate-induced intracellular free calcium ([Ca2+]i) accu mulation and cell death in cultured hippocampal neurons. Fifteen minut es of exposure to either 100 mu M or 1 mM glutamate uniformly induced a marked increase in [Ca2+]i, with delayed recovery and massive neuron al death under the conditions of both 37 degrees C and 30 degrees C. T he study indicated that brain hypothermia cannot save neurons once glu tamate is released during ischemia, and that intraischemic hypothermia in vivo probably prevents the development of ischemic neuronal injury by suppressing extracellular glutamate release.