Metabotropic glutamate receptor-induced disinhibition is mediated by reduced transmission at excitatory synapses onto interneurons and inhibitory synapses onto pyramidal cells.

Previous studies suggest that activation of metabotropic glutamate receptors (mGluRs) reduces GABA-mediated synaptic inhibition in area CA1 of the hippocampus. However, the mechanisms involved in this disinhibition are not known. We report that mGluR activation reduces both the GABAA and GABAB receptor-mediated components of evoked inhibitory postsynaptic potentials (IPSPs) by reducing transmission at excitatory synapses onto inhibitory interneurons and inhibitory synapses onto CA1 pyramidal cells.