Role of metabotropic glutamate receptors in dendritic coordination between excitation and inhibition
Coordination between excitation and inhibition is essential for proper functioning of neuronal circuits. We recently discovered that by repeated stimulation of excitatory synapses, the formation of a nearby inhibitory bouton onto the same dendrite can be triggered. We showed that NMDA receptor activation is required, but not sufficient, to induce bouton growth. Here, we hypothesized that additional activation of metabotropic glutamate receptors 5 (mGluR5s) is necessary. We used two-photon microscopy to image crossings between CA1 pyramidal cell dendrites and GABAergic axons in organotypic hippocampal slices of GAD65-GFP mice. We stimulated multiple dendritic spines close to the crossing axon using two-photon glutamate uncaging (30x @0.5Hz). Our results indicate that inhibitory bouton growth seems to be independent of mGluR5 activation.