university demonstrates that glutamate can also be used to induce inhibitory postsynaptic potentials in neurons. this study explains that metabotropic glutamate receptors feature activated g proteins in dopamine neurons that induce phosphoinositide hydrolysis. the resultant products bind to inositol triphosphate (ip3) receptors through calcium ion channels. the calcium comes from stores and activate potassium conductance, which causes a pure inhibition in the dopamine cells. the changing levels of synaptically released glutamate creates an excitation through the activation of ionotropic receptors, followed by the inhibition of metabotropic glutamate receptors.