Fig. 2.
Hypothermia reduced NMDA receptor-dependent Ca2+ entry. (A) Prior to stimulation with 50 μM glutamate, hippocampal neurons exhibited similar 340/380 baseline ratios of 0.30±0.01 for neurons in the 31°C group and 0.31±0.02 for neurons in the 37°C group (black bars). Upon stimulation with 37°C glutamate, 340/380 ratios peaked to 0.636±0.04, which is significantly elevated compared to baseline. When neurons were stimulated with 31°C glutamate, 340/380 ratios peaked to 0.38±0.01 (grey bars). *P<0.001 compared to baseline; #P<0.001 between 31°C and 37°C peaks, one way ANOVA followed by post-hoc Tukey test, n=7 plates per condition. (B) Representative pseudocolor images obtained from baseline neuron (left panel), neuron stimulated with 37°C glutamate (top right panel), and neuron stimulated with 31°C glutamate (bottom right panel). Neurons exhibited elevated [Ca2+]i upon 37°C stimulation and a diminished response to 31°C stimulation.