Biomaterial Database

Alinidine modifies the pacemaker current in sheep Purkinje fibers. 1987

D J Snyders, and P P Van Bogaert

Department of Physiology, University of Antwerp (R.U.C.A.), Belgium.

(1) The "specific bradycardic agent" alinidine reduces the slope of the diastolic depolarization in sinoatrial tissue and Purkinje fibers. In short Purkinje fibers of sheep, alinidine (28 microM) decreased the pacemaker current by a dual action. The voltage dependence of if activation was shifted in the hyperpolarizing direction by 7.8 +/- 0.6 mV (n = 18, p less than 0.001) and the conductance of the fully activated if current was reduced to 73 +/- 2% (n = 18, p less than 0.001) of its control value. These effects were reversible and dose-dependent. (2) Ionophoretic injections of alinidine caused reversible reductions of the diastolic depolarization rate and simultaneous transient hyperpolarizing shifts of the if activation range. (3) Some prolongation of the action potential duration was observed at 28 microM and more pronounced at higher concentration. This was presumably the consequence of a reduction by alinidine of outward repolarizing current carried by the background inward rectifier and plateau current ix. (4) The action of alinidine on if resulted in a slower activation of a reduced fraction of the pacemaker current at the maximal diastolic potential level. This explains the decrease of the diastolic depolarization rate observed in Purkinje fibers.

UI	MeSH Term	Description	Entries
D007478	Iontophoresis	Therapeutic introduction of ions of soluble salts into tissues by means of electric current. In medical literature it is commonly used to indicate the process of increasing the penetration of drugs into surface tissues by the application of electric current. It has nothing to do with ION EXCHANGE; AIR IONIZATION nor PHONOPHORESIS, none of which requires current.	Iontophoreses
D007700	Kinetics	The rate dynamics in chemical or physical systems.
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
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
D003000	Clonidine	An imidazoline sympatholytic agent that stimulates ALPHA-2 ADRENERGIC RECEPTORS and central IMIDAZOLINE RECEPTORS. It is commonly used in the management of HYPERTENSION.	Catapres,Catapresan,Catapressan,Chlophazolin,Clofelin,Clofenil,Clonidine Dihydrochloride,Clonidine Hydrochloride,Clonidine Monohydrobromide,Clonidine Monohydrochloride,Clopheline,Dixarit,Gemiton,Hemiton,Isoglaucon,Klofelin,Klofenil,M-5041T,ST-155,Dihydrochloride, Clonidine,Hydrochloride, Clonidine,M 5041T,M5041T,Monohydrobromide, Clonidine,Monohydrochloride, Clonidine,ST 155,ST155
D006329	Heart Conduction System	An impulse-conducting system composed of modified cardiac muscle, having the power of spontaneous rhythmicity and conduction more highly developed than the rest of the heart.	Conduction System, Heart,Conduction Systems, Heart,Heart Conduction Systems,System, Heart Conduction,Systems, Heart Conduction
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
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001683	Biological Clocks	The physiological mechanisms that govern the rhythmic occurrence of certain biochemical, physiological, and behavioral phenomena.	Biological Oscillators,Oscillators, Endogenous,Pacemakers, Biological,Biologic Clock,Biologic Oscillator,Biological Pacemakers,Clock, Biologic,Clocks, Biological,Oscillator, Biologic,Oscillators, Biological,Pacemaker, Biologic,Pacemakers, Biologic,Biologic Clocks,Biologic Oscillators,Biologic Pacemaker,Biologic Pacemakers,Biological Clock,Biological Oscillator,Biological Pacemaker,Clock, Biological,Clocks, Biologic,Endogenous Oscillator,Endogenous Oscillators,Oscillator, Biological,Oscillator, Endogenous,Oscillators, Biologic,Pacemaker, Biological