Figure 1

Energy efficiency of AP increases as temperature increases. A. Sodium entry ratio (SER, defined as ∫I_Na(t)dt/(C_m∆V), where I_Na(t) is Na+ current, C_m is capacitance, ∆V is the change in voltage during an AP) vs temperature. For both squid axon and cortical axon models, increasing temperature strongly decreases SER during AP. At 18^o C, SER is approximately 4, while at 37^o C, SER reaches 1.89 and 1.41. B. Cortical AP, I_Na and I_K at 18 and 37^o C, respectively. C. The inactivation level of Na⁺ channel increases as temperature increases, indicating a more closed state for a high temperature, decreasing the leaky Na+ through membrane. D. Decrease of Na+ activation time constant as temperature increases. E. Decrease of Na+ inactivation time constant as temperature increases.