Cyclic GMP-PKG signaling plays a crucial role in neuropsychiatric disorders such as depression/anxiety that is of ten characterized with oxidative stress and neuronal cell apopto sis.Phosphodiesterase 2 (PDE2) is linked to cGMP-PKG signa ling and highly expressed in the limbic brain regions including hippocampus and amygdala, which may be important in treat ment of depression and anxiety through regulation of oxidative stress and apoptosis.