AZIN2 and bipolar disorder: Interestingly, high dose of agmatine has been shown to disrupt prepulse inhibition of acoustic startle reflex, an operational measure of sensorimotor gating (a benchmark test for schizophrenia61), in rats.62 In the present study, we were unable to investigate how arginine decarboxylase (the biosynthesis enzyme of agmatine) changed in schizophrenia, as fresh tissue is required for measuring its activity.63 Bernstein et al.64 reported strongly upregulated agmatinase, which converts agmatine to putrescine, in the hippocampus of patients with mood disorders (unipolar and bipolar depression).