Influence of formamide on the electrical and mechanical properties of the guinea pig ventricle.
1. Guinea pig papillary muscle in vitro upon exposure of Formamide (FMD) exerts a dose dependent positive inotropic effect. 2. The increase in tension developed by papillary muscle is associated with a marked decrease in the duration of the action potential. 3. The increase in extracellular calcium concentration does not modify the positive inotropic effect, but increases the duration of the action potential. 4. FMD markedly potentiate the increase in tension induced by caffeine 3 M suggesting a possible synergetic effect upon the release of Ca2+ ions from the S.R. 5. These experiments suggest that FMD increases the intracellular calcium concentration by exerting a direct action on intracellular calcium stores.
Garcia
X
X
Department of Physiology, School of Medicine, Universidad Nacional Autónoma de México, Mexico.
del Castillo
J
J
Gijón
E
E
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D004594:Electrophysiology; D005559:Formamides / Q000494:pharmacology*; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D006352:Heart Ventricles / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism; D010210:Papillary Muscles / Q000187:drug effects / Q000502:physiology; D016276:Ventricular Function
D005559:Formamides; D002110:Caffeine; D002118:Calcium