Involvement of Nitric Oxide in Learning & Memory Processes (Report‪)‬

Introduction It has been known for many years that NO which is a gas made up of two most common gases in the atmosphere, occurs in the biological system. NO crosses cell membranes freely and plays a role as a neurotransmitter in the brain. The function of NO in the hypothalamus has largely been implicated in learning process and in memory formation (1). In order to establish evidence for the involvement of NO in learning and memory processes, the experimental findings that demonstrated synthesis of NO and the neuronal action of NO at the time when experimental animals were trained to learn and then to remember a specific task, were reviewed in this article. In addition, the cognitive effects of agents that increase or decrease NO concentration in the hypo-thalamus were also included. Further, the reports indicating the beneficial effects of NO elevating agents in alleviating cognitive disorder caused by pathological conditions, by the deposition of endogenous substance like beta amyloid in the brain of patients with Alzheimer's disease (AD) and the toxicities of therapeutic agents were also included.