Nitric Oxide in Psychiatry

Nitric oxide (NO) is an important molecule, and was named“molecule of the year” by the journal Science in 1992. NO plays a pivotal role in physiological and pathological processes in the brain. There is no doubt that excitability and neurotransmitter release are modulated by NO in the brain. The effects of NO are mediated primarily by cGMP and glutamate. The NO-cGMP system is required for activity-dependent synaptic plasticity in various brain regions, including the hippocampus, amygdala, striatum, cerebral cortex, and cerebellum. There appear to be mechanisms that limit the excitatory effects of the NO-cGMP system, such as inhibition of NMDA receptor responses or enhancing the release of GABA. NO participates in a wide range of physiological activities, ranging from regulation of blood pressure to processes underlying some forms of learning and memory. NO is not a specific marker of disease, because its widespread role in cell metabolism could suggest its involvement in many disorders. The wide spectrum of NO-associated psychiatric disorders includes neurodegenerative diseases, such as Alzheimer’s disease, as well as schizophrenia and mood and eating disorders. Agents intended to intervene in the NO pathway may provide a new approach to the treatment of certain neuropsychiatric disorders, including schizophrenia, mood and eating disorders, and neurodegenerative diseases.