Basal Activity of Group I mGlu Receptors Sets Resting Membrane Potential in MNTB Neurons

Group I mGlu receptors (mGluR-I) modulate neuronal excitability through different ionic mechanisms. These receptors have been identified in both the Medial Nucleus of the Trapezoid Body (MNTB) neuron and its presynaptic calyx of Held nerve terminal. MNTB is an auditory brainstem nucleus that reliably responds to high-frequency stimuli (HFS) up to 800 Hz in rodents. Previously, we have shown that a selective mGluR-I agonist (DHPG) modulates MNTB neuron excitability through a membrane potential depolarization and inward current shift. Here, we determine under what conditions endogenous glutamate activates these receptors to elucidate the role of mGluR-I on neurotransmission at the Calyx of Held/MNTB synapse.