Developmental changes in the response of cardiac Purkinje fibers to SC-72-14.
We used standard microelectrode techniques to study the effects of SC-72-14, a monoclonal antibody to eel electroplax, and tetrodotoxin (TTX) on the electrophysiological properties of neonatal and adult canine Purkinje fibers. SC-72-14, 7 ng/ml, depressed maximum upstroke potential (Vmax) and membrane responsiveness of adult but not neonatal fibers. In contrast, we previously had shown TTX to have a greater effect on neonatal than adult fibers (29). Even in the presence of SC-72-14, TTX continued to have a greater effect on the neonatal fibers. The effects of TTX and SC-72-14 were cumulative over the concentration range studied, and our results are consistent with their acting at different sites.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D000911:Antibodies, Monoclonal; D004285:Dogs; D006321:Heart / Q000254:growth & development*; D007473:Ion Channels / Q000276:immunology / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D009200:Myocardial Contraction; D011689:Purkinje Cells / Q000502:physiology*; D012964:Sodium / Q000502:physiology; D013779:Tetrodotoxin / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D007473:Ion Channels; D013779:Tetrodotoxin; D012964:Sodium