A relatively simple differential screening test for GABA or glycine antagonists using rat electroretinography.
Intravitreal injection of GABA- and glycine-antagonists had specific and reversible effects on the ERG of rats. For example, picrotoxin induced characteristic rhythmic potentials. The effect was common to other GABA-antagonists, such as bicuculline, N-methylbicuculline and penicillin G. Strychnine caused the appearance of a- and c-like waves in response to low intensity flash stimuli in addition to the suppression of the b-wave commonly seen with agents such as asparate following higher intensity flash stimuli. The strychnine-like effect was common to other glycine-antagonist tested, such as brucine, morphine and laudanosine. The quanternization of the glycine-antagonists abolished the strychnine-like activity and endowed the ability to induce the rhythmic potentials characteristic of GABA-antagonists. This relatively simple method of observing either rhythmic potentials or a negative deflection (a-like wave) to a low intensity stimulus (about 1.0 log unit above dark threshold) in the ERG should be useful for the rapid screening of the predicted and new GABA--and glycine-antagonists.
D000200:Action Potentials / Q000187:drug effects; D000613:Aminobutyrates / Q000037:antagonists & inhibitors*; D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology; D004353:Drug Evaluation, Preclinical; D004596:Electroretinography; D018756:GABA Antagonists; D005998:Glycine / Q000037:antagonists & inhibitors*; D008297:Male; D008722:Methods; D010852:Picrotoxin / Q000494:pharmacology; D051381:Rats; D012621:Seasons; D013331:Strychnine / Q000494:pharmacology; D013997:Time Factors
D000613:Aminobutyrates; D001224:Aspartic Acid; D018756:GABA Antagonists; D005998:Glycine; D010852:Picrotoxin; D013331:Strychnine