Effect of alpha-allocryptopine on transient outward potassium current in rabbit ventricular myocytes. 2008

Y Li, and S Wang, and Y Liu, and Z Li, and X Yang, and H Wang, and Y Wen, and Y Chen
Electrophysiology of Laboratory, Institute of Geriatric Cardiology, Chinese PLA General Hospital, Beijing, China.

OBJECTIVE To investigate the mechanism of alpha-allocryptopine-induced inhibition of the transient outward potassium current (I(to)) in rabbit left-ventricular myocytes. METHODS We used the whole-cell patch-clamp technique to record the I(to) in the myocytes, which were isolated from the rabbit left ventricle by a Langendorff-perfusion device. RESULTS Allocryptopine decreased the amplitude and the density of the I(to) in a concentration-dependent (range from 1 to 100 microM with an IC(50) value of 37 +/- 8 microM) and frequency- or use-independent manner. At a test potential of +50 mV, the peak current density of I(to) was decreased from 21.56 +/- 3.24 to 13.37 +/- 2.86 pA/pF by 30 microM allocryptopine. The fast time constant of I(to) inactivation was reduced from 9.8 +/- 1.8 to 5.7 +/- 0.7 ms and the slow time constant of I(to) was reduced from 50.8 +/- 9.0 to 32.2 +/- 12.7 ms by 30 microM allocryptopine. The inactivated curve slope was changed from -19.2 +/- 7.1 to -7.5 +/- 0.6 mV, while the half-activated voltage and activated curve slope and half-inactivated voltage values were not affected by allocryptopine. Transmural heterogeneity of the I(to) was decreased in the presence of allocryptopine. At a test potential of +50 mV, the densities of I(to) were reduced by 28.6% (epimyocardium), 50.3% (mid-myocardium) and 20.1% (endocardium) after exposure to 30 microM allocryptopine.Transmural dispersion of the I(to) was reduced from 11.2 +/- 1.2 to 4.7 +/- 0.6 pA/pF by 30 microM allocryptopine. CONCLUSIONS Allocryptopine produced a blocking effect on the I(to) in cardiac myocytes, which may be an important mechanism in its antiarrhythmic effect.

UI MeSH Term Description Entries
D011817 Rabbits A burrowing plant-eating mammal with hind limbs that are longer than its fore limbs. It belongs to the family Leporidae of the order Lagomorpha, and in contrast to hares, possesses 22 instead of 24 pairs of chromosomes. Belgian Hare,New Zealand Rabbit,New Zealand Rabbits,New Zealand White Rabbit,Rabbit,Rabbit, Domestic,Chinchilla Rabbits,NZW Rabbits,New Zealand White Rabbits,Oryctolagus cuniculus,Chinchilla Rabbit,Domestic Rabbit,Domestic Rabbits,Hare, Belgian,NZW Rabbit,Rabbit, Chinchilla,Rabbit, NZW,Rabbit, New Zealand,Rabbits, Chinchilla,Rabbits, Domestic,Rabbits, NZW,Rabbits, New Zealand,Zealand Rabbit, New,Zealand Rabbits, New,cuniculus, Oryctolagus
D004195 Disease Models, Animal Naturally-occurring or experimentally-induced animal diseases with pathological processes analogous to human diseases. Animal Disease Model,Animal Disease Models,Disease Model, Animal
D004305 Dose-Response Relationship, Drug The relationship between the dose of an administered drug and the response of the organism to the drug. Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D006352 Heart Ventricles The lower right and left chambers of the heart. The right ventricle pumps venous BLOOD into the LUNGS and the left ventricle pumps oxygenated blood into the systemic arterial circulation. Cardiac Ventricle,Cardiac Ventricles,Heart Ventricle,Left Ventricle,Right Ventricle,Left Ventricles,Right Ventricles,Ventricle, Cardiac,Ventricle, Heart,Ventricle, Left,Ventricle, Right,Ventricles, Cardiac,Ventricles, Heart,Ventricles, Left,Ventricles, Right
D000465 Algorithms A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task. Algorithm
D000704 Analysis of Variance A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable. ANOVA,Analysis, Variance,Variance Analysis,Analyses, Variance,Variance Analyses
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
D000889 Anti-Arrhythmia Agents Agents used for the treatment or prevention of cardiac arrhythmias. They may affect the polarization-repolarization phase of the action potential, its excitability or refractoriness, or impulse conduction or membrane responsiveness within cardiac fibers. Anti-arrhythmia agents are often classed into four main groups according to their mechanism of action: sodium channel blockade, beta-adrenergic blockade, repolarization prolongation, or calcium channel blockade. Anti-Arrhythmia Agent,Anti-Arrhythmia Drug,Anti-Arrhythmic,Antiarrhythmia Agent,Antiarrhythmia Drug,Antiarrhythmic Drug,Antifibrillatory Agent,Antifibrillatory Agents,Cardiac Depressant,Cardiac Depressants,Myocardial Depressant,Myocardial Depressants,Anti-Arrhythmia Drugs,Anti-Arrhythmics,Antiarrhythmia Agents,Antiarrhythmia Drugs,Antiarrhythmic Drugs,Agent, Anti-Arrhythmia,Agent, Antiarrhythmia,Agent, Antifibrillatory,Agents, Anti-Arrhythmia,Agents, Antiarrhythmia,Agents, Antifibrillatory,Anti Arrhythmia Agent,Anti Arrhythmia Agents,Anti Arrhythmia Drug,Anti Arrhythmia Drugs,Anti Arrhythmic,Anti Arrhythmics,Depressant, Cardiac,Depressant, Myocardial,Depressants, Cardiac,Depressants, Myocardial,Drug, Anti-Arrhythmia,Drug, Antiarrhythmia,Drug, Antiarrhythmic,Drugs, Anti-Arrhythmia,Drugs, Antiarrhythmia,Drugs, Antiarrhythmic
D001600 Berberine Alkaloids A group of related plant alkaloids that contain the BERBERINE heterocyclic ring structure. Berbines,Alkaloids, Berberine
D018408 Patch-Clamp Techniques An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used. Patch Clamp Technique,Patch-Clamp Technic,Patch-Clamp Technique,Voltage-Clamp Technic,Voltage-Clamp Technique,Voltage-Clamp Techniques,Whole-Cell Recording,Patch-Clamp Technics,Voltage-Clamp Technics,Clamp Technique, Patch,Clamp Techniques, Patch,Patch Clamp Technic,Patch Clamp Technics,Patch Clamp Techniques,Recording, Whole-Cell,Recordings, Whole-Cell,Technic, Patch-Clamp,Technic, Voltage-Clamp,Technics, Patch-Clamp,Technics, Voltage-Clamp,Technique, Patch Clamp,Technique, Patch-Clamp,Technique, Voltage-Clamp,Techniques, Patch Clamp,Techniques, Patch-Clamp,Techniques, Voltage-Clamp,Voltage Clamp Technic,Voltage Clamp Technics,Voltage Clamp Technique,Voltage Clamp Techniques,Whole Cell Recording,Whole-Cell Recordings

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