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Published on: October 13, 2014
Nitric oxide and cGMP modulate retinal glutamate receptors
1Department of Physiology, University of Kentucky, Lexington 40536-0084, USA.
Journal of Neurophysiology
|October 1, 1996
Summary
Nitric oxide (NO) reduces glutamate receptor activity in retinal horizontal cells. This NO-mediated signaling pathway involves cyclic guanosine monophosphate (cGMP) and may protect cells from excitotoxicity.
Area of Science:
- Neuroscience
- Retinal Physiology
- Molecular Signaling
Background:
- Glutamate receptors are crucial for synaptic transmission and cellular communication in the vertebrate retina.
- Retinal horizontal cells play a key role in visual processing and are targets for synaptic modulation.
Purpose of the Study:
- To investigate the role of nitric oxide (NO) in modulating glutamate receptor activity in retinal horizontal cells.
- To elucidate the signaling pathway involved in NO-mediated regulation of kainate receptors.
Main Methods:
- Whole-cell voltage clamp recordings were used to measure currents in dissociated retinal horizontal cells.
- Application of glutamate, kainate, NO donors, NO scavengers, and specific inhibitors were employed.
- Endogenous nitric oxide synthase activity was stimulated using L-arginine.
Main Results:
- Nitric oxide donors significantly reduced kainate-evoked currents in horizontal cells by approximately 50%.
- The NO effect was mediated by cyclic guanosine monophosphate (cGMP) and involved guanylate cyclase and protein kinase G.
- Stimulation of endogenous nitric oxide synthase also reduced kainate responses.
Conclusions:
- Nitric oxide acts as a modulator of glutamate receptor function in retinal horizontal cells.
- This NO-cGMP pathway may regulate synaptic function based on retinal adaptational states.
- The mechanism may offer protection against glutamate excitotoxicity in horizontal cells.
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