H19 and hereditary pheochromocytoma-paraganglioma: Depolarization by treating with 100 mM KCl for 5 min resulted in the undulating phosphorylation of GSK‐3[beta] at Ser‐9 in SH‐SY5Y human neuroblastoma cells, in H19 −7/IGF‐IR rat embryonic hippocampal cells, and in PC12 rat pheochromocytoma cells (Lee et al., 2005).