GPR55 and pheochromocytoma: It has been suggested that LPI activated GPR55 is able to induce exocytosis and catecholamine release from the neuroendocrine pheochromocytoma-12 cells [18,35] Furthermore, the activation of dorsal root ganglion (DRG) neurons by GPR55 increases intracellular calcium and inhibits potassium current through M-type potassium channel [30].