[Suppression of platelet activating factor effects (PAF) on the retina by G-proteins inhibitors].

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.