Investigation of the antifibrillatory activity of some anticonvulsant gamma-aminobutyric acid-transaminase inhibitors in the rabbit isolated heart: comparison with phenytoin and mexiletine.
1 The electrical stimulation and ventricular fibrillation thresholds were measured in the Langendorff-perfused rabbit heart by application of rectangular impulses of 3 ms duration and increasing current at frequencies of 4 and 20 Hz respectively. 2 Perfusion with either phenytoin or mexiletine produced significant dose-dependent increases in both thresholds. 3 Perfusion with four anticonvulsant inhibitors of gamma-aminobutyric acid (GABA)-transaminase, aminooxyacetic acid, gamma-acetylenic GABA, gamma-vinyl GABA and sodium valproate, up to a concentration of 20 microgram/ml, had no significant effect on either threshold. 4 The results suggest that these compounds, unlike phenytoin and mexiletine, are devoid of antifibrillatory activity.
D000612:4-Aminobutyrate Transaminase / Q000037:antagonists & inhibitors*; D000818:Animals; D000889:Anti-Arrhythmia Agents; D000927:Anticonvulsants / Q000494:pharmacology*; D004558:Electric Stimulation; D005260:Female; D006321:Heart / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D008801:Mexiletine / Q000494:pharmacology*; D009206:Myocardium / Q000201:enzymology; D010672:Phenytoin / Q000494:pharmacology*; D011437:Propylamines / Q000494:pharmacology*; D011817:Rabbits; D000637:Transaminases / Q000037:antagonists & inhibitors*; D014693:Ventricular Fibrillation / Q000503:physiopathology
D000889:Anti-Arrhythmia Agents; D000927:Anticonvulsants; D011437:Propylamines; D008801:Mexiletine; D010672:Phenytoin; D000637:Transaminases; D000612:4-Aminobutyrate Transaminase