Voltage dependence of the peak attenuation. (A) Red circles: voltage dependence of the minimum (notch) ΔF/F value observed in di-8-ANEPPS transients from a fiber exposed to NMG-Tyrode containing 0.5 µM isradipine. Black circles: steady-state amplitude of di-8-ANEPPS transients recorded from the same fiber after replacing NMG-Tyrode with TEA-Tyrode. (B) Voltage dependence of peak IKV (red circles) and leak current (black circles) measured from the same fiber and conditions as in A. (C) Voltage dependence of the percent peak attenuation calculated from data in A. (D) Red circles: voltage dependence of the mean notch ΔF/F calculated from a family of di-8-ANEPPS transients in 10 fibers exposed to NMG-Tyrode (with no added Ca blocker). Black circles: steady-state amplitude of di-8-ANEPPS transients recorded from the same population of fibers after replacing NMG-Tyrode with TEA-Tyrode. (E) Voltage dependence of the mean peak IKV (circles) determined from the same fiber and conditions as in D. (F) Voltage dependence of the mean percent peak attenuation calculated from data in D. Error bars represent SEM.
