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Published on: September 18, 2015
Metabotropic transmitter actions in auditory thalamus
D W Schwarz1, F Tennigkeit, E Puil
1Rotary Hearing Center, Department of Pharmacology and Therapeutics, University of British Columbia, Vancouver, Canada.
Acta Oto-Laryngologica
|October 18, 2001
Summary
Metabotropic glutamate receptors (mGluRs) in the auditory thalamus enhance neural excitability, promoting alertness. GABA(B) receptor activation suppresses auditory signal transfer by hyperpolarizing neurons.
Area of Science:
- Neuroscience
- Auditory System Research
- Thalamic Function
Background:
- The ventral medial geniculate body (MGBv) is the primary auditory thalamus.
- MGBv neurons receive excitatory (glutamate) and inhibitory (GABA) inputs.
- Feedback from the auditory cortex also uses glutamate and GABA.
Purpose of the Study:
- Investigate the effects of metabotropic receptors on MGBv neuron excitability.
- Determine the roles of glutamate and GABA in auditory signal processing.
Main Methods:
- Whole-cell recording in rat thalamus slice preparation.
- Application of metabotropic glutamate receptor (mGluR) agonist ACPD.
- Application of GABA(B) receptor agonist baclofen.
Main Results:
- ACPD depolarized MGBv neurons, switching firing from burst to tonic mode, enhancing alertness.
- ACPD activated an inward current dependent on extracellular sodium.
- Baclofen hyperpolarized MGBv neurons by activating an inwardly rectifying potassium current, suppressing firing.
Conclusions:
- mGluR activation enhances MGBv neuron excitability, potentially mediating auditory alertness.
- GABA(B) receptor activation inhibits MGBv neurons, suppressing auditory signal transmission.
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