[Electrotropic acetylcholine action on the mammalian auricle by means of the "phase plane" trajectories of the action potential].
A single sucrose gap techniques has been used to study action potentials and phase plane trajectories of them in atrial trabeculae of the rabbit. Using polynomial representations of current-voltage relationships a model of membrane action potential of atrial myocardial fibres is described and allows an interpretation of recording data from the phase plane trajectories. Our findings show: 1. Increasing extracellular calcium concentration increases a potassium conductivity of the atrial membrane. 2. An anomalous rectification concerning repolarizing currents in atrial fibres decreases with increasing extracellular calcium. 3. Acetylcholine (3.10(-4) g.cm-3) abolishes the anomalous rectification. These results are discussed in relation to previous electrophysiological studies of negative electrotropic effects of acetylcholine in cardiac muscle.
D000109:Acetylcholine / Q000494:pharmacology*; D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D016275:Atrial Function; D001322:Autoanalysis; D002118:Calcium / Q000494:pharmacology; D004553:Electric Conductivity; D006325:Heart Atria / Q000187:drug effects; D007700:Kinetics; D008433:Mathematics; D008564:Membrane Potentials / Q000187:drug effects; D008722:Methods; D009200:Myocardial Contraction / Q000187:drug effects*; D011188:Potassium / Q000378:metabolism; D011817:Rabbits
D000109:Acetylcholine; D011188:Potassium; D002118:Calcium
Untersuchungen elektrotroper Azetylcholinwirkungen mit Hilfe der "phase plane"-Darstellung von Aktionspotentialen des Vorhofmyokards.