iGluR (ionotropic glutamate receptor) is a ligand-gated ion channel that is activated by the neurotransmitter glutamate. iGluR are integral membrane proteins compose of four large subunits that form a central ion channel pore. Sequence similarity among all known glutamate receptor subunits, including the AMPA, kainate, NMDA, and δ receptors.

AMPA receptors are the main charge carriers during basal transmission, permitting influx of sodium ions to depolarise the postsynaptic membrane. NMDA receptors are blocked by magnesium ions and therefore only permit ion flux following prior depolarisation. This enables them to act as coincidence detectors for synaptic plasticity. Calcium influx through NMDA receptors leads to persistent modifications in the strength of synaptic transmission.