Jan 10, 2014

Modulation of short-term plasticity in the corticothalamic circuit by group III metabotropic glutamate receptors

The Journal of Neuroscience : the Official Journal of the Society for Neuroscience
Christine L Kyuyoung, John R Huguenard


Recurrent connections in the corticothalamic circuit underlie oscillatory behavior in this network and range from normal sleep rhythms to the abnormal spike-wave discharges seen in absence epilepsy. The propensity of thalamic neurons to fire postinhibitory rebound bursts mediated by low-threshold calcium spikes renders the circuit vulnerable to both increased excitation and increased inhibition, such as excessive excitatory cortical drive to thalamic reticular (RT) neurons or heightened inhibition of thalamocortical relay (TC) neurons by RT. In this context, a protective role may be played by group III metabotropic receptors (mGluRs), which are uniquely located in the presynaptic active zone and typically act as autoreceptors or heteroceptors to depress synaptic release. Here, we report that these receptors regulate short-term plasticity at two loci in the corticothalamic circuit in rats: glutamatergic cortical synapses onto RT neurons and GABAergic synapses onto TC neurons in somatosensory ventrobasal thalamus. The net effect of group III mGluR activation at these synapses is to suppress thalamic oscillations as assayed in vitro. These findings suggest a functional role of these receptors to modulate corticothalamic transmissi...Continue Reading

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Mentioned in this Paper

Reticular Dysgenesis
Receptors, Metabotropic Glutamate
End Plate Potentials
Neuronal Plasticity
Calcium Spikes
Structure of Cortex of Kidney
Neural Pathways

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