Effects of benzodiazepines on frog ERG.
Effect of flurazepam (water-soluble benzodiazepine) on the amplitude and time course of ERG waves was investigated in superfused frog eyecups (Rana ridibunda). Flurazepam (50 and 100 microM) had inhibitory effect on the b- and d-wave amplitude, which was not accompanied with significant changes in their implicit time. Flurazepam potentiated the depressant effect of GABA (2.5 and 5 mM) on the b- and d-wave amplitude. The inhibitory effect of flurazepam was not blocked by 50 microM bicuculline (BCC), (GABA(A) antagonist), although the blocker markedly potentiated the b- and d-wave amplitude. The suppressive effect of flurazepam on the b- but not d-wave amplitude was blocked by 100 microM BCC. Our results indicate existence of functional benzodiazepine regulatory sites on GABA(A) receptors in distal frog retina.
Department of Physiology, Medical Faculty, Medical University, 1431 Sofia, Bulgaria. popova@medfac.acad.bg
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Popova
D000818:Animals; D001569:Benzodiazepines / Q000494:pharmacology*; D001640:Bicuculline / Q000494:pharmacology; D004596:Electroretinography / Q000187:drug effects* / Q000379:methods; D005479:Flurazepam / Q000494:pharmacology; D066298:In Vitro Techniques; D011895:Rana ridibunda; D012160:Retina / Q000187:drug effects* / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D001569:Benzodiazepines; D005680:gamma-Aminobutyric Acid; D005479:Flurazepam; D001640:Bicuculline