AMPA-type ionotropic glutamate receptor (AMPA receptor) (AMPAR)

The AMPA-type ionotropic glutamate receptor (AMPAR) is a tetrameric ligand-gated ion channel widely expressed in the central nervous system, mediating the majority of fast excitatory neurotransmission. The receptor is composed of four subunits (GluA1–4), each containing an extracellular amino-terminal domain, a ligand-binding domain (which includes the glutamate binding site), a transmembrane domain forming the cation channel pore, and an intracellular C-terminal domain. Binding of glutamate at the ligand-binding domain induces conformational changes that rapidly open the ion channel, allowing sodium and (in some forms) calcium influx, which depolarizes the postsynaptic neuron and triggers synaptic signaling[1][2][5][7]. AMPA receptors are dynamically regulated at synapses and play key roles in synaptic plasticity, learning, and memory. Dysfunction or abnormal regulation of AMPA receptors is implicated in epilepsy, neurodegeneration, and a range of psychiatric and neurological disorders. Several drugs, including the anti-seizure medication perampanel, act as noncompetitive antagonists at the AMPA receptor[6][8]. Pharmacological modulation of different AMPAR conformations and subunit compositions poses both opportunities and challenges for selective therapy, as broad inhibition can lead to CNS depression and other adverse effects[3][6]. The AMPA receptor glutamate binding site itself is the orthosteric site targeted by endogenous glutamate, but drug development has also focused on allosteric sites due to the difficulty of achieving specificity and minimizing side effects at the orthosteric site[2][3].

Other names

Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptorIonotropic glutamate receptor AMPA typeGluA receptorGlutamate receptor 1-4 (GluA1, GluA2, GluA3, GluA4 subunits)

Competitive antagonism at the glutamate binding site; Non-competitive antagonism (binding at allosteric sites, inhibiting receptor activity); Positive allosteric modulation (AMPAkines increase channel opening probability or duration); Negative allosteric modulation (prevent channel gating or desensitization)