• ADP and ADPr acts on the same receptor, and ADPr increases [Ca²⁺]_i by activating the P2Y1 receptor.

• Tolbutamide closes the K_ATP channels, such closure of the K_ATP channels in the presence of some inward cation currents through the TRPV1 channels leads to depolarization to the threshold for the activation of the voltage gated calcium channels to increase the [Ca²⁺]_i (figure).

Figure : Closure of the K_ATP channels as well as cation currents through the TRPV1 channels are required for depolarization of the β- cell that leads to activation of voltage gated Ca²⁺ channels.