GRM7 and Huntington disease: mGLUR7, like many glutamate receptors, can also serve as an autoreceptor to inhibit neurotransmitter release at the presynapse.98-100 Activation of group III receptors, such as mGLUR7, may potentially increase the viability of the GABAergic-projecting neurons in the striatum selectively lost in HD as a compensatory mechanism during disease progression.