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bioRxiv · 10.1101/2020.06.03.130724

Group II metabotropic glutamate receptors modulate sound evoked and spontaneous activity in the mouse inferior colliculus

Kristaponyte, I.·Beebe, N. L.·Young, J. W.·Shanbhag, S. J.·Schofield, B. R.·Galazyuk, A. V.
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Abstract

Little is known about the functions of group II metabotropic glutamate receptors (mGluRs2/3) in the inferior colliculus (IC)--a midbrain structure that is a major integration region of the central auditory system. We investigated how these receptors modulate sound-evoked and spontaneous firing in the mouse IC in vivo. We first performed immunostaining and tested hearing thresholds to validate VGAT-ChR2 transgenic mice on a mixed CBA/CaJ x C57BL/6J genetic background. Transgenic animals allowed for optogenetic cell type identification. Extracellular single neuron recordings were obtained before and after pharmacological mGluR2/3 activation. We observed increased sound-evoked firing--as assessed by the rate-level functions--in a subset of both GABAergic and non-GABAergic IC neurons following mGluR2/3 pharmacological activation. These neurons also displayed elevated spontaneous excitability and were distributed throughout the IC area tested, suggesting a widespread mGluR2/3 distribution in the mouse IC.

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Kristaponyte, I., Beebe, N. L., Young, J. W., Shanbhag, S. J., Schofield, B. R., Galazyuk, A. V.. 2020-06-04. Group II metabotropic glutamate receptors modulate sound evoked and spontaneous activity in the mouse inferior colliculus. https://doi.org/10.1101/2020.06.03.130724

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