(A) Cartoon interpretation of the molecular events that occur during consecutive time intervals (sections a-g, also identified by intermittent gray shading in (A)-(B)) of the current recording in (B). Membrane, light cyan; nvTRPM2 protein, dark gray; Ca2+ ions, magenta spheres; ADPR, green letters ‘A’; direction of Ca2+ flow, yellow arrows. (B) In the presence of 1 mM external Ca2+, at −20 mV membrane potential, a fraction of the macroscopic nvTRPM2 current evoked by cytosolic exposure to 100 μM ADPR +125 μM free Ca2+ survives cytosolic Ca2+ removal, and subsides only upon removal of ADPR (see Figure 5E). A second application of 100 μM ADPR, without cytosolic Ca2+, activates a current comparable to that which survived prior Ca2+ removal. Note delayed current activation following exposure to ADPR alone.