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Search for the Source of the Retinal Relaxing Factor
Laura Vanden Daele1, Charlotte Boydens1, Joke Devoldere2
1a Department of Pharmacology , Ghent University , Ghent , Belgium.
Current Eye Research
|July 4, 2018
Summary
The cellular source of retinal relaxing factor (RRF) remains unidentified, as it is not released by vascular or glial cells. RRF release in chickens shows both calcium-dependent and independent characteristics.
Area of Science:
- Ophthalmology
- Vascular Biology
- Cell Biology
Background:
- Retinal relaxing factor (RRF) is an unknown paracrine factor released by retinal tissue.
- RRF causes smooth muscle cell relaxation, impacting vascular function.
Purpose of the Study:
- To identify the cellular origin of RRF within retinal tissue.
- To investigate RRF release mechanisms, including voltage-dependent sodium channel activation.
- To determine the calcium dependency of RRF release.
Main Methods:
- Isometric tension measurements of mouse femoral arteries.
- Evaluation of vasorelaxing effects of chicken retinas and cultured retinal cells.
- Inhibition studies using cell type-specific inhibitors.
- Assessment of RRF release with veratridine (sodium channel activator) and varying calcium concentrations.
Main Results:
- Chicken retinas induced vasorelaxation, but Müller cell cultures did not.
- Inhibitors of glial cells and microglia did not affect RRF-induced relaxation.
- Veratridine did not enhance RRF release in mouse retinal tissue.
- RRF release in chicken retinas was partially dependent on calcium.
Conclusions:
- RRF is not released by vascular or glial cells; its source remains unclear.
- Veratridine does not stimulate RRF release in mice.
- Chicken RRF release exhibits both calcium-dependent and independent properties.
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