TH and pheochromocytoma: PC12 was originally established from a pheochromocytoma of adrenal origin, and neuronally differentiated PC12 cells are estimated to have characteristics of sympathetic neurons (Greene and Tischler, 1976), and possess some characteristics of dopaminergic neurons, as evidenced by their expression of tyrosine hydroxylase and their ability to incorporate MPP +, etc. (Grima et al., 1985, Jin et al., 2007, Kumer and Vrana, 1996).