The temperature sensitvity of miniature endplate currents is mostly governed by channel gating: Evidence from optimized recordings and Monte Carlo simulations

The temperature dependence of miniature endplate current (MEPC) amplitude (A(c)), 20-80% rise time (t(r)), and 90-33% fall-time (t(f)) was determined for lizard (Anolis carolinensis) intercostal muscle using broadband extracellular (EC) and voltage clamp (VC) recordings. Voltage clamp methods were optimized for the fast MEPC rising phase using custom electronics. From 0-43 degrees C, A(c) increased by approximately 4.2-fold, while t(r) and t(f) decreased by approximately 3.6- and approximately 9.5-fold, respectively. Arrhenius plots were smoothly curved, with small apparent Q(10) (A(c)) or (Q(10))(-1) (t(r) and t(f)) values mostly well below 2.0. Nearly identical extracellular and voltage clamp results ruled out measurement artifacts, even for the shortest t(r) values (