Figure 5. Tachyphylaxis of heat-evoked inward currents is independent of intra- and extracellular calcium.

Each graph shows the mean heat-evoked peak currents of three consecutive heat stimuli. A, tachyphylaxis of I_heat under control conditions (n = 19). B, tachyphylaxis investigated when extracellular Ca²⁺ was buffered with. 10 mm EGTA (n = 8). C, tachyphylaxis in neurones where intracellular Ca²⁺ was buffered with 10 mm BAPTA (n = 13). Data are presented as means ± s.e.m. (***P ≤ 0·001, **P ≤ 0·01, *P ≤ 0·05 versus peak of 1st stimulus, Newman-Keuls post hoc test). Currents decreased significantly across the repeated heat stimulation, but buffering intra- or extracellular Ca²⁺ did not change the degree of tachyphylaxis.