ADPRP is a novel true TRPM2 partial agonist with distinctive kinetic features. (A) Macroscopic T5L-TRPM2 currents in response to cytosolic application of saturating Ca²⁺ (black bars) and either 32 µM ADPR (dark blue bars) or increasing concentrations of ADPRP (red bars). (B) Dose–response curves for fractional current activation by ADPR (dark blue; replotted from Fig. 1 D) and ADPRP (red). Currents were normalized to those measured in 32 µM ADPR. Solid lines are fits to the Hill equation with parameters plotted in the panel. (C) Macroscopic T5L-TRPM2 current repeatedly activated by brief exposures to 32 µM ADPR (dark blue bars) or 100 µM ADPRP (red bars), in the continued presence of saturating Ca²⁺ (black bars). Current decay time courses upon nucleotide removal were fitted by single-exponential functions (colored curves) with time constants indicated (in seconds). (D) Average T5L-TRPM2 current relaxation time constants (in seconds) upon sudden removal of saturating ADPR (dark blue) or ADPRP (red) in the maintained presence of Ca²⁺. Error bars represent mean ± SEM.