AMPA receptor
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The AMPA receptor (AMPAR) is a non-NMDA-type ionotropic transmembrane receptor for glutamate that mediates fast synaptic transmission in the central nervous system. Its name is derived from its ability to be activated by the artificial glutamate analog, AMPA. It is the most commonly found receptor in nervous system.
Structure and function
AMPA receptors are composed of four subunits, designated as GluR1-GluR4 (alternatively called GluRA-GluRD), and is probably a tetramer. Most receptors are either homomers of GluR1 or GluR3, or symmetric 'dimer of dimers' of GluR2 and either GluR1 or GluR3. The AMPA receptor s' permeability to calcium and other ions such as sodium and potassium, is governed by the GluR2 subunit. Post-transcriptional modification to the so-called Q/R editing site of the GluR2 mRNA determines whether the resulting AMPAR will be calcium-permeable. In particular, GluR2(Q) is permeable to calcium, while the calcium permeability of GluR2(R) is negligible. Almost all of the GluR2 subunits in the CNS are of the GluR2(R) form. This means that the principal ion gated by AMPA receptors is sodium.
Related topics
External links
- Glutamate receptors - structures and functions (http://www.bris.ac.uk/Depts/Synaptic/info/glutamate.html)
- AMPA receptors - pharmacology (http://www.bris.ac.uk/Depts/Synaptic/info/pharmacology/AMPA.html)