Biomaterial Database

Electrophysiological studies on effects of AQ-A 39 in the isolated guinea pig heart and myocardial preparations. 1982

S Hohnloser, and J Weirich, and H Homburger, and H Antoni

An isolated perfused hearts as well as in papillary muscles and in Purkinje fibres, the influence of 5,6-dimethoxy-2(3[alpha-(3,4-dimethoxy)phenylethyl)-methylamino]propyl)phthalimidine hydrochloride (AQ-A 39) on the electrical activity was examined (concentration range of AQ-A 39 2.15--10.7 x 10-(5) mol/l). In the isolated heart AQ-A 39 (2.15 x 10(-5) mol/l) reduced the sinus frequency by about 50%. Higher concentrations (up to 10.7 x 10(-5) mol/l) exerted only little additional influence. Similar effects of AQ-A 39 were observed in Ba2+ induced pacemakers in the ventricular myocardium. In Purkinje fibres (K+e 2.7 x 10(-3) mol/l) AQ-A 39 (2.15 x 10(-5) mol/l) reduced the rate of spontaneous discharge to a considerable extent. In papillary muscles as well as in Purkinje fibres the terminal phase of repolarization of the action potential was markedly prolonged without a detectable influence on the resting potential or the maximal rate of rise (Vmax). In the Ba2+ treated depolarized myocardium Vmax was considerably reduced by AQ-A 39. The effects of AQ-A 39 are discussed in view of their ionic mechanisms as well as of the therapeutic application of the drug.

UI	MeSH Term	Description	Entries
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
D010797	Phthalimides	The imide of phthalic acids.
D011690	Purkinje Fibers	Modified cardiac muscle fibers composing the terminal portion of the heart conduction system.	Purkinje Fiber,Fiber, Purkinje,Fibers, Purkinje
D002317	Cardiovascular Agents	Agents that affect the rate or intensity of cardiac contraction, blood vessel diameter, or blood volume.	Cardioactive Agent,Cardioactive Drug,Cardiovascular Agent,Cardiovascular Drug,Cardioactive Agents,Cardioactive Drugs,Cardiovascular Drugs,Agent, Cardioactive,Agent, Cardiovascular,Drug, Cardioactive,Drug, Cardiovascular
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
D004594	Electrophysiology	The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
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