Memory loss is an abnormal degree of forgetfulness and inability to retrieve past experiences and events. Nootropic agents act on brain to improve the cognitive function. They are used for the treatment of amnesia or dementia, occurring due to the disturbance of neuronal mechanism in various pathological conditions. Long-term potentiation (LTP) is a well-accepted molecular mechanism of learning and memory. Neurotransmitters such as GABA, Nor-epinephrine, dopamine, acetylcholine etc and their receptors are also reported to modulate learning and memory. Impairment in the physiological process of LTP produces memory deficits. Moreover, antioxidant, metabolic enhancers, chelators, nerve growth factors and calcium channel blockers have been reported to decline the progress of neurodegeneration and improve the cognition. Drugs, obtained from various plant sources, are now tested in animals and humans with hope of inventing newer therapeutic agents.

doi : 10.5214/ans.0972.7531.2009.160308

Competing interests: None.     Source of Funding: None

Received Date: 29 May 2009     Revised Date: 24 June 2009     Accepted Date: 11 July 2009