Intracellular and Intercellular Messengers Produced by Metabotropic (Qp), AMPA, and NMDA Excitatory Amino Acid Receptors

Glutamate (Glu) receptors can be classified into two main classes: the ionotropic receptor class and the G protein-coupled receptor class (G protein = GTP-binding protein). The first class includes the N-methyl-D-aspartate (NMDA), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA), and kainate (KA) receptors. Recently, several clones (at least six) encoding for functional AMPA and one clone encoding for functional KA receptors have been sequenced [1–5].