MAPK3 and psychiatric disorder: The roles of AKT-GSK3β and ERK1/2 in psychiatric disorders have been discussed in numerous reports on bipolar disorder and schizophrenia.5,6,26,27 Many reports have implicated that the same pathway is involved in the therapeutic mechanisms of various mood stabilizers, anti-psychotics and ECT.28-31 This study provides further evidence for the above implications by demonstrating that AKT-GSK3β and ERK1/2 are regulated by KCl-induced depolarization, a possible therapeutic model of ECS and neuronal activity, and by MK-801, a drug that induces psychotomimetic effects.