Biomaterial Database

Effects of disopyramide on transmembrane action potentials in guinea-pig papillary muscles. 1981

M Kojima

The effects of disopyramide on the transmembrane action potential in guinea-pig papillary muscles were studied with special reference to the dependence of the effects on the external concentrations of K+ ([K+]0), stimulation rates, and diastolic intervals. Disopyramide, 2 micrometer, prolonged the 90% action potential duration (ADP90) without changing the maximum rate of phase 0 depolarization (Vmax) (class 3 action), whereas disopyramide, 20 micrometer, reduced Vmax, (class 1 action). The class 3 action was prominent in 2.7 and 5.4 mM [K+]0, at 0.25--1 Hz, and so was the class 1 action in 8.1 mM [K+]0, at 2--5 Hz. Disopyramide, 20 micrometer, enhanced the rate-dependent reduction in Vmax only in 8.1 mM [K+]0. Neither concentration of disopyramide altered the recovery kinetics of APD90 in the premature responses in three [K+]0, but slowed that of Vmax only in 8.1 mM [K+]0. These results indicate that the manifestation of class 3 action of disopyramide is favored with low concentrations of the drug, low [K+]0, and low stimulation rates, whereas the reverse is true in the class of the class 1 action.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008297	Male		Males
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D010210	Papillary Muscles	Conical muscular projections from the walls of the cardiac ventricles, attached to the cusps of the atrioventricular valves by the chordae tendineae.	Muscle, Papillary,Muscles, Papillary,Papillary Muscle
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D011725	Pyridines	Compounds with a six membered aromatic ring containing NITROGEN. The saturated version is PIPERIDINES.
D004206	Disopyramide	A class I anti-arrhythmic agent (one that interferes directly with the depolarization of the cardiac membrane and thus serves as a membrane-stabilizing agent) with a depressant action on the heart similar to that of guanidine. It also possesses some anticholinergic and local anesthetic properties.	Diisopyramide,Disopyramide Monohydrochloride,Disopyramide Phosphate,Disopyramide Phosphate (1:1),Disopyramide Phosphate (1:1), (+-)-Isomer,Disopyramide Phosphate (1:1), (R)-Isomer,Disopyramide Phosphate (1:1), (S)-Isomer,Disopyramide, (+-)-Isomer,Disopyramide, (R)-Isomer,Disopyramide, (S)-Isomer,Disopyramide, D-Tartrate (1:1), (S)-Isomer,Disopyramide, L-Tartrate (1:1), (R)-Isomer,Disopyramide, L-Tartrate (1:1), (S)-Isomer,Disopyramide, L-Tartrate (1:2), (+-)-Isomer,Disopyramide, L-Tartrate, (S)-isomer,Norpace,Palpitin,Palpitine,Rhythmodan,Ritmilen,Rythmilen,SC-13957,SC 13957,SC13957
D006168	Guinea Pigs	A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.	Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
D006321	Heart	The hollow, muscular organ that maintains the circulation of the blood.	Hearts
D000200	Action Potentials	Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.	Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential