any of various receptors that bind and respond to the excitatory neurotransmitter glutamate. Glutamate receptors are found on the surface of most neurons. There are two main divisions of these receptors: ionotropic receptors and metabotropic receptors. Ionotropic glutamate receptors are further divided into three classes: NMDA receptors, AMPA receptors, and kainate receptors. Metabotropic glutamate receptors (mGlu or mGluR) are subdivided into several classes denoted by subscript numbers (i.e., mGlu1, mGlu2, etc.).