AMPA Receptors

AMPA receptors are cation-permeable, ligand-gated ion channels. Like other members of this family, AMPA receptors are named based on a compound that was found to be selective for these receptors; α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA). They consist of GluA1-4 subunits that assemble as homomers or heteromers to form functional receptors. Each subunit is encoded by a different gene, and alternative versions of the subunits may be produced by gene splicing. There is a large heterogeneity within the exact subunit conformation of endogenous AMPA receptors, with brain region specific expression seen for some splice variants.

The subunit composition of an AMPA receptor determines its physiological properties, in particular the extent to which these ion channels are permeable to Ca²⁺. Calcium permeability can be traced to a single amino acid residue within the re-entrant loop of subunit GluA2, termed the Q/R site. In GluA1, A3 and A4 subunits a glutamine (Q) is found at this site, however in the GluA2 subunit an arginine (R) is present, due to post-translation modification. AMPA receptors containing a GluA2 subunit are relatively impermeable to Ca²⁺, while receptors lacking this subunit are highly Ca²⁺ permeable. This site also regulates single channel conductance of AMPA receptors, and their sensitivity to some toxins.

AMPA receptors play a key role in synaptic plasticity, particularly in long-term potentiation (LTP), which is thought to be the cellular correlate of learning and memory. LTP describes an increase in excitatory postsynaptic potential (EPSP) size, which starts when glutamate binds to postsynaptic AMPA and NMDA receptors. Activation of AMPA receptors by ligand binding leads to opening of the pore and enables Na⁺ influx into the postsynaptic neuron causing depolarization. Once depolarization is strong enough to displace Mg²⁺ ions from the ion pore of NMDA receptors, these receptors allow more Na⁺ and Ca²⁺ to enter the cell. Entry of Ca²⁺ results in upregulation of trafficking of AMPA receptors to the membrane, through a CaMKII - Ras - MAPK signaling pathway. Phosphorylation of CaMKII caused by the rise in intracellular Ca²⁺ in turn phosphorylates AMPA receptors, increasing their single channel conductance.

External sources of pharmacological information for AMPA Receptors :

• IUPHAR Receptor Code

• BJP Guide

Literature for AMPA Receptors

Tocris offers the following scientific literature for AMPA Receptors to showcase our products. We invite you to request* your copy today!

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Addiction Poster

The key feature of drug addiction is the inability to stop using a drug despite clear evidence of harm. This poster describes the brain circuits associated with addiction, and provides an overview of the main classes of addictive drugs and the neurotransmitter systems that they target.

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Alzheimer's Disease Poster

Alzheimer's disease (AD) is a debilitating and progressive neurodegenerative disease and the most common cause of dementia, affecting approximately 30% of individuals aged over 85 years. This poster summarizes the cellular and molecular mechanisms of AD.

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Depression Poster

Major depressive disorder is characterized by depressed mood and a loss of interest and/or pleasure. Updated in 2015 this poster highlights presynaptic and postsynaptic targets for the potential treatment of major depressive disorder, as well as outlining the pharmacology of currently approved antidepressant drugs.

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Parkinson's Disease Poster

Parkinson's disease (PD) causes chronic disability and is the second most common neurodegenerative condition. This poster outlines the neurobiology of the disease, as well as highlighting current therapeutic treatments for symptomatic PD, and emerging therapeutic strategies to delay PD onset and progression.

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AMPA Receptor Gene Data