Hypothermia prevents biphasic glutamate release and corresponding neuronal degeneration after transient spinal cord ischemia in the rat.

1. Spinal cord ischemia evoked a biphasic increase in CSF-Glu during 20 min of ischemia (40%) and at 2 hr after reperfusion (70%) in the nontreated group that was attenuated by all treated groups. But MK-801 (15 micrograms i.t.) did not affect the increased Glu at 2 hr (80%). 2. The argyrophilia observed in laminae II-V at 8 hr after reperfusion was attenuated by hypothermia (33 degrees C) and combination with MK-801, but the attenuation was less with MK-801. 3. Mild hypothermia attenuated the biphasic increase in CSF-Glu and corresponding development of neuronal damage after spinal cord ischemia. 4. Mild hypothermia with NMDA antagonism did not yield any further effects, suggesting that hypothermia itself plays a pivotal role in the protection.