Presynaptic metabotropic glutamate receptors regulate glutamatergic input to dopamine neurons in the ventral tegmental area.

The ventral tegmental area is part of the midbrain dopamine system and is crucially involved in reward, motivation and drug abuse. The activity of dopamine neurons within this region is controlled by synaptic input. In particular, excitatory glutamatergic inputs are important for the switch from regular firing into burst firing. In the present manuscript we determined the role of presynaptic metabotropic glutamate receptors (mGluRs) in the regulation of spontaneous glutamate release of terminals projecting to dopamine cells in the ventral tegmental area of mice. We show that group III mGluRs regulate spontaneous glutamate release and this effect is most likely mediated by mGluR7. The presynaptic dampening of glutamatergic input might open new perspectives in the treatment of drug addiction.