TRPM2 currents are enhanced in hippocampal pyramidal neurons with time in vitro. With 1 mM ADPR included in the patch pipette, TRPM2 currents developed slowly following repeated (1/60 sec) applications NMDA (100 μM, for 5 sec). TRPM2 currents were quantified by removing extracellular calcium and amplitude was normalized to cell capacitance. NMDA applications are indicated with solid lines. Calcium-free application is depicted as a dashed line (A) Representative trace of TRPM2 currents recorded at 14 DIV (B) Representative trace of TRPM2 currents recorded at 25 DIV. (C) Current density at 14, 20, and 26 DIV (n = 5 per group) were compared by one-way ANOVA followed by post-hoc Tukey's test. A significant increase in TRPM2 current density between 14 and 26 DIV was observed (p < 0.05). (D) NMDAR current density is not significantly increased over time in vitro (p = 0.76).