MAPK3 and pheochromocytoma: Earlier we reported that RJ induces neurite outgrowth from cultured PC12 cells [8, 9], a cell line of rat pheochromocytoma, via adenosine A2A receptors, and enhances the phosphorylation of both extracellular signal-regulated kinase 1 or 2 (ERK1/2) and cAMP-response element-binding protein (CREB) in both PC12 cells [9, 10] and cultured neural stem/progenitor cells (NS/NPCs) [11].