FIGURE 4.

Mutations in S4 and the S4–S5 linker alter temperature sensitivity of TRPV1. A, representative recordings of whole cell current responses to application of 25–48 °C heat ramp (10 °C/s) at −70 mV. B, Arrhenius plot of whole cell currents obtained from representative cells shown in A, normalized at 25 °C (ordinate, log scale) and plotted against the reciprocal of absolute temperature (abscissa). Temperature coefficients Q₁₀ were determined for each cell over the temperature range where the Arrhenius plot was linear (dashed lines). C, effects of mutations on Q₁₀. Dotted line indicates the value at which the temperature dependence of the thermally induced currents is considered to be nonspecific, i.e. close to that of the aqueous diffusion limit (∼2). NT denotes nontransfected cells. Each bar is the mean ± S.E. (error bars); n = 33 for wild type and 3–15 for mutants.