AMPA receptor

German: AMPA-Rezeptor

1 Definition

AMPA receptors are unspecific cation channels belonging to the subgroup of ionotropic glutamate receptors. They are widespread in the central nervous system and constitute the most common form of neurotransmitter receptors.

2 Biochemistry

AMPA receptors consist of 4 subunits with 3 transmembrane domains each. The subunits each comprise about 900 amino acids and have a mass of about 100 kDa. So far, four different AMPA receptors have been described, referred to as GluR1 through 4.

The relative conductivity for calcium ions through AMPA receptors varies with the specific arrangement of the individual subunits. GluR1, GluR3, and GluR4 are permeable for calcium ions. The GluR2 subunit is impermeable for calcium ions due to an enzymatic modification effected by the adenosine deaminase enzyme. This modification of the GluR2 domain is an exchange of glutamine for arginine.

Biochemical relatives of AMPA receptors are NMDA and Kainate receptors. AMPA and Kainate are synthetic ligands that can only bind to those two receptors, in contrast to glutamate which can bind to a larger number of receptors.