Figure 7

Diminished effects of 2-APB on nvTRPM2-K908N. (a) 2-APB fails to evoke currents even at elevated extracellular Ca²⁺. (b) 2-APB becomes effective after pre-stimulation with ADPR. In contrast to the experiment shown in panel a, ADPR was present in the pipette solution, at a roughly half-maximal concentration (0.6 mM). After complete inactivation of the ADPR-induced current, 2-APB (1 mM) was applied and did evoke sizeable currents. (c) 2-APB becomes effective in elevated extracellular Ca²⁺ after pre-stimulation with ADPR at a sub-threshold concentration. Current recording was performed in a bath solution with 10 mM Ca²⁺ and a pipette solution with 0.15 mM ADPR, which did not induce currents in this combination. Currents were only evoked by subsequent application of 2-APB (1 mM) with the typical properties. All experiments were repeated at least three times confirming the results.