Figure 1. Single-channel currents recorded in the outside-out configuration from HEK293 cells that were stably expressing TRPC4β. (A) Representative single-channel current traces were recorded at voltages ranging from +80 to -140 mV. The holding potentials were 80, 30, -60 and -120 mV in A. GTPγS (200 μM) was intracellularly applied to activate the TRPC4 channel under the condition of 125 mM [Cs⁺]_i and 125 mM [Cs⁺]_o and nominally [Ca²⁺]_o-free. (B) The corresponding I-V relationships from each potential are shown in the upper panel and the red line represents the fit to obtain a unitary conductance. The plot of NPo was estimated from each potential (bottom panel).