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[Suppression of platelet activating factor effects (PAF) on the retina by G-proteins inhibitors]
1Laboratoire de Biophysique, Facultés de Médecine et de Pharmacie, Clermont-Ferrand.
Abstract:
The Platelet Activating Factor (PAF) have been shown to alter the transretinal potential recorded from light stimulated isolated retina. In the present study, we investigated the effect of cholera and pertussis toxins on PAF-induced electroretinogram (ERG) impairment. Administrated alone, 2.10(-7) M PAF induced a very marked and rapid drop in the b-wave amplitude of the ERG. When 75 micrograms/l of cholera toxin was coadministrated with PAF (2.10(-7) M) into the perfusion solution, the fall of the b-wave was not observed, suggesting that PAF effect on retinal function was mediated through GTP-binding protein (G-protein). Similarly, low-dose of pertussis toxin (5 micrograms/l) 1) were sufficient to antagonize PAF (2.10(-7) M) consequence on the ERG. Our results suggest that the irreversible and deleterious effect of PAF on ERG is mediated by a G-protein mechanism, located in the neural retina.
Insights
Platelet Activating Factor (PAF) impairs retinal function by reducing the electroretinogram (ERG) b-wave. Cholera and pertussis toxins block this effect, indicating a G-protein mechanism mediates PAF
Area of Science:
- Ophthalmology and visual neuroscience.
- Cellular and molecular biology.
Context:
- Platelet-Activating Factor (PAF) is implicated in altering retinal function.
- The electroretinogram (ERG) measures retinal electrical activity.
- G-protein signaling pathways are crucial in cellular responses.
Purpose:
- To investigate the role of G-protein signaling in PAF-induced electroretinogram (ERG) impairment.
- To determine if cholera toxin and pertussis toxin can antagonize PAF's effects on the retina.
Summary:
- Platelet-Activating Factor (PAF) significantly reduced the b-wave amplitude in isolated retina ERGs.
- Co-administration of cholera toxin or pertussis toxin prevented the PAF-induced ERG impairment.
- These findings suggest PAF exerts its deleterious effects on retinal function via a G-protein mechanism.
Impact:
- Elucidates the specific molecular pathways involved in PAF-induced retinal dysfunction.
- Highlights the potential involvement of G-protein coupled receptors in retinal pathophysiology.
- Provides insights into potential therapeutic targets for retinal disorders involving PAF.