Metabotropic glutamate receptors as therapeutic targets for cognitive disorders.

Since more than one decade, metabotropic glutamate receptors have been under investigation as targets for various CNS disorders such as anxiety, pain, depression, schizpohrenia, Alzheimer's disease and Parkinson's disease. It has been shown that some mGluRs play a crucial role in cognitive processes such as learning and memory, which was initially, demonstrated using knockout mice for each receptor subtype. Later, selective pharmacological tools were developed allowing more specific examinations of the involvement of mGluR1-8 in various forms of learning and memory. Ligands for group I and II mGluRs have been proposed as promising candidates for the treatment of cognitive disorders such as schizophrenia, Fragile X syndrome, Alzheimer's and Parkinson's disease and post traumatic stress disorder, of which some have made it to clinical testing. The present paper reviews relevant data on the role of mGluRs in learning and cognition processes focusing on their utility as targets for cognition enhancement in several CNS diseases.