Figure 4.

Cd²⁺-mediated attenuation of voltage-induced changes in C_m in a type III taste cell. A, The sequence of voltage pulses applied to the taste cell clamped at −70 mV. B, Control depolarization-induced changes in C_m, recorded before the application of Cd²⁺ Tyrode's solution. C, Depolarization-induced changes in C_m recorded 3 min after the application of a Tyrode's solution containing 0.5 mm Cd²⁺. D, Recovery of depolarization-induced changes in C_m after 5 min wash of the cell with Tyrode's. The traces in B–D were low-pass filtered (100 Hz, Gaussian filter). E, Average amplitude of depolarization-induced increases in C_m, determined from the last five voltage pulses (−20 to +20 mV) on five cells was significantly reduced (p < 0.05) after the application of Cd²⁺. There was a significant (*p < 0.05; one-way ANOVA with Tukey's multiple-comparison test) recovery after washout of the Cd²⁺ Tyrode's. F, Time-dependent amplitude reduction of depolarization-induced C_m in type III taste cells (n = 6 cells). The voltage pulse protocol was applied to a single cell in 5 min intervals. The response in C_m was averaged for the voltage pulses from −20 to +20 mV. The line represents the best fit to the equation of the form: C_m (fF) = (3.28 ± 0.63)e^{(0.127 ± 0.047)*time(min)}, yielding a time constant of the decay of ∼8 min. Error bars represent SEM.