Fig. 3: Pleiotropic actions of mGlu3 receptors and potential relevance to the pathophysiology and treatment of PD.

Presynaptic mGlu3 receptors are localized in the preterminal region of the axon terminal, and share with mGlu2 receptors the ability to inhibit glutamate release. This mechanism converges with the anti-inflammatory effect in microglia and the induction of TGF-β and GDNF in astrocytes to support the potential disease-modifying effect of mGlu3 receptor agonists or PAMs in PD. Postsynaptic mGlu3 receptors functionally interact with mGlu5 receptors, a mechanism implicated in the potential pro-cognitive effects of mGlu3 receptor agonists or PAMs. For simplicity, mGlu3 receptors are illustrated as monomers.