Inhibition of platelet-activating factor-induced retinal impairments by cholera and pertussis toxins.
Platelet-activating factor (PAF) has been shown to alter the trans-retinal potential recorded from light-stimulated isolated retina. In the present study, we investigated the effect of cholera and pertussis toxins on PAF-induced impairment of the electroretinogram (ERG). Administered alone, 2 x 10(-7) M PAF induced a very marked and rapid drop in the b-wave amplitude. When 75 micrograms/l of cholera toxin was coadministered with PAF in the perfusion solution, no b-wave drop was observed, suggesting that the effect of PAF on retinal function was mediated by GTP-binding protein (G protein). Similarly, a low dose of pertussis toxin (5 micrograms/l) was sufficient to antagonize the action of PAF 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.
Laboratoire de Biophysique, Faculté de Médecine, Clermont-Ferrand, France.
J
J
Cluzel
M
M
Doly
N G
NG
Bazan
B
B
Bonhomme
P
P
Braquet
D000818:Animals; D002772:Cholera Toxin / Q000494:pharmacology*; D004338:Drug Combinations; D004596:Electroretinography / Q000187:drug effects; D005260:Female; D019204:GTP-Binding Proteins / Q000502:physiology; D008027:Light; D037342:Pertussis Toxin; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000187:drug effects / Q000502:physiology*; D015398:Signal Transduction; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D004338:Drug Combinations; D010972:Platelet Activating Factor; D010566:Virulence Factors, Bordetella; D002772:Cholera Toxin; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins