FIGURE 2.

Glutamate receptors: structure and function. NMDARs bind glutamate, glycine, Mg²⁺, Zn²⁺, and polyamines. Composed from seven subunits (one NR1, four NR2, and two NR3), their function is determined by the combination of NR1 and NR2 subunits. NMDARs form channels that are more permeable to Ca²⁺ than Na⁺ and K⁺. Kainate and AMPA receptors interact only with glutamate and their specific agonists, and their associated channels are more permeable to Na⁺ and K⁺ than Ca²⁺. mGluRs are G-protein coupled receptors and trigger a second messenger cascade. They are found both at the pre- and post-synaptic neurons, subunits of metabotropic receptors are also expressed in microglia.