Voltage tunes mGlu5 receptor function, impacting synaptic transmission

Abstract

Voltage sensitivity is a common feature of many membrane proteins, including some G-protein coupled receptors (GPCRs). However, the functional consequences of voltage sensitivity in GPCRs are not well understood. In this study, we investigated the voltage sensitivity of the post-synaptic metabotropic glutamate receptor mGlu5 and its impact on synaptic transmission. Using biosensors and electrophysiological recordings in non-excitable HEK293T cells or neurons, we found that mGlu5 receptor function is optimal at resting membrane potentials. We observed that membrane depolarization significantly reduced mGlu5 receptor activation, Gq-PLC/PKC stimulation, Ca2+ release, and mGlu5 receptor-gated currents through TRPC6 channels or NMDA receptors. Notably, we report a previously unknown activity of the NMDA receptor at the resting potential of neurons, enabled by mGlu5. Our findings suggest that mGlu5 receptor activity is directly regulated by membrane voltage which may have a significant impact on synaptic processes and pathophysiological functions.