Glycine receptors support excitatory neurotransmitter release in developing mouse visual cortex
Portia A Kunz1, Alain C Burette, Richard J Weinberg
1Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Campus Box 7545, 115 Mason Farm Rd, Chapel Hill, NC 27599-7545, USA.
The Journal of Physiology
|September 19, 2012
Summary
Presynaptic glycine receptors (GlyRs) facilitate glutamate release in the developing mouse visual cortex, a process dependent on chloride gradients and calcium entry. This facilitatory role is absent in adult brains, indicating developmental regulation.
Area of Science:
- Neuroscience
- Developmental Biology
- Neurophysiology
Background:
- Glycine receptors (GlyRs) are crucial in the central nervous system, with dysfunction linked to neurological disorders.
- While typically inhibitory, presynaptic GlyRs (preGlyRs) can facilitate excitatory neurotransmitter release via unknown mechanisms.
Purpose of the Study:
- To investigate the role of GlyRs in facilitating excitatory neurotransmitter release in the mouse visual cortex.
- To elucidate the molecular mechanisms underlying preGlyR-mediated facilitation of glutamate release.
Main Methods:
- Whole-cell recordings in mouse visual cortex slices.
- Electrophysiological analysis of neurotransmitter release.
- Investigation of ion transport mechanisms and calcium signaling.
Main Results:
- Presynaptic GlyRs facilitate glutamate release in the developing visual cortex but not in the adult brain.
- This facilitation relies on the chloride gradient maintained by the Na(+)-K(+)-2Cl(-) cotransporter and Ca(2+) influx via voltage-gated channels.
- Glial glycine transporter 1 regulates extracellular glycine levels and preGlyR activation.
Conclusions:
- Glycine receptors play a developmentally regulated role in modulating excitatory neurotransmitter release in the neocortex.
- The findings reveal a novel mechanism for controlling cortical excitation during early development.
