Functional role of cholinoceptors and purinoceptors in human isolated atrial and ventricular heart muscle

Jakob, H; Oelert, H.; Rupp, Johanna; Nawrath, Hermann

doi:10.1111/j.1476-5381.1989.tb12579.x

Cited by 31 publications

(21 citation statements)

References 25 publications

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“…Our results are in general agreement with those represented in the literature (Jakob et al 1989). Action potentials recorded from working cardiomyocytes (n = 12) had an amplitude of 71 ± 8 mV, a resting potential of −63 ± 10 mV, an overshoot of 8 ± 6 mV, and a duration of 452 ± 65 ms.…”

Section: Baseline Electrophysiological Propertiessupporting

confidence: 83%

“…Action potential configuration and resting membrane potential from human atrial cardiomyocytes were comparable to those reported in the literature (Jakob et al 1989) but were clearly different from mechanically induced potential configuration and resting membrane potential of fibroblasts. The resting potential of human atrial fibroblasts was −15·9 ± 2·1 mV.…”

Section: Baseline Electrophysiological Propertiessupporting

confidence: 70%

“…The possible role of fibroblasts under physiological and pathophysiological conditions in human hearts necessitates the study of the electrophysiological parameters of these cells from human atrial myocardium. methods Experiments were performed on human right atrial trabeculae (Jakob et al 1989) from 16 patients (65-78 years old) undergoing open heart bypass surgery. Right atrial function of the patients was clinically normal.…”

Section: Introductionmentioning

confidence: 99%

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Mechanically Induced Potentials in Fibroblasts from Human Right Atrium

Kamkin

Kiseleva

Wagner

et al. 1999

Experimental Physiology

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summaryIt has been shown that cardiac fibroblasts of the human heart are electrically non-excitable and mechanosensitive. The resting membrane potential of these cells is −15·9 ± 2·1 mV and the membrane resistance is 4·1 ± 0·1 GÙ. Rhythmic contractions of the myocardium associated with stretch of the surrounding tissue produce reversible changes in the membrane potential of cardiac fibroblasts. These mechanically induced potentials (MIPs) follow the rhythm of myocardial contractions. Simultaneous recording of the action potential of cardiomyocytes and MIPs of cardiac fibroblasts demonstrates a delay of 40·0 ± 0·4 ms after the action potential before the appearance of the MIP. Contraction produces a MIP which is more positive or more negative than the reversal potential -the membrane potential due to current injection at which the MIP reverses its direction. Regardless of the initial orientation of the MIP, intracellular polarization increases the amplitude towards the reversal potential if the background MIP had depolarized the membrane or away from the reversal potential if the initial background MIP had hyperpolarized the membrane. Artificial intracellular polarization changed the amplitude but not the frequency of the MIP.

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Section: Baseline Electrophysiological Propertiessupporting

confidence: 83%

Section: Baseline Electrophysiological Propertiessupporting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

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Mechanically Induced Potentials in Fibroblasts from Human Right Atrium

Kamkin

Kiseleva

Wagner

et al. 1999

Experimental Physiology

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“…It is well known that there exist heterogeneities in human atrial AP shape. AP morphology and characteristics can vary both from patient to patient and from region to region in the atria (45) and have variously been classified into "types" or patterns (8,10,27,57). Rather than require that the resultant AP morphology adhere to a specific experimental recording as in previous models of the adult human atrial myocyte (7,40), we have chosen to arrive at a morphology for which accurate reproduction of observed behaviors of individual currents has been the focus.…”

Section: Ap Waveformsmentioning

confidence: 99%

K⁺current changes account for the rate dependence of the action potential in the human atrial myocyte

Maleckar

Greenstein

Giles

et al. 2009

American Journal of Physiology-Heart and Circulatory Physiology

123

162

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Maleckar MM, Greenstein JL, Giles WR, Trayanova NA. K ϩ current changes account for the rate dependence of the action potential in the human atrial myocyte. Am J Physiol Heart Circ Physiol 297: H1398 -H1410, 2009. First published July 24, 2009 doi:10.1152/ajpheart.00411.2009.-Ongoing investigation of the electrophysiology and pathophysiology of the human atria requires an accurate representation of the membrane dynamics of the human atrial myocyte. However, existing models of the human atrial myocyte action potential do not accurately reproduce experimental observations with respect to the kinetics of key repolarizing currents or rate dependence of the action potential and fail to properly enforce charge conservation, an essential characteristic in any model of the cardiac membrane. In addition, recent advances in experimental methods have resulted in new data regarding the kinetics of repolarizing currents in the human atria. The goal of this study was to develop a new model of the human atrial action potential, based on the Nygren et al. model of the human atrial myocyte and newly available experimental data, that ensures an accurate representation of repolarization processes and reproduction of action potential rate dependence and enforces charge conservation. Specifically, the transient outward K ϩ current (It) and ultrarapid rectifier K ϩ current (IKur) were newly formulated. The inwardly recitifying K ϩ current (IK1) was also reanalyzed and implemented appropriately. Simulations of the human atrial myocyte action potential with this new model demonstrated that early repolarization is dependent on the relative conductances of I t and IKur, whereas densities of both I Kur and IK1 underlie later repolarization. In addition, this model reproduces experimental measurements of rate dependence of I t, IKur, and action potential duration. This new model constitutes an improved representation of excitability and repolarization reserve in the human atrial myocyte and, therefore, provides a useful computational tool for future studies involving the human atrium in both health and disease. ionic model; repolarization; potassium current ACCURATE REPRESENTATION of the ionic currents of the human atrial myocyte is essential for the ongoing investigation of human atrial electrophysiology and pathophysiology. It is now well established that the elucidation of mechanisms underlying the complex phenomena that occur in highly integrative systems, such as atrial tissue, requires that experimental data be incorporated such that models are both accurate and biophysically based.Within the past decade, advances in experimental methods have resulted in a much-improved characterization of repolarizing currents in the human atria (21, 50, 59 -61). New insights into the underlying channel isoforms responsible for these K ϩ currents are also now available (32,41,53,54,56). However, findings regarding essential repolarization processes in the human atria have been incorporated into none of the available mathematical models of the actio...

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“…1993 , Ray & MacLeod 1993). Jakob et al . (1989 ) showed that carbachol in human atrial heart muscle decreased the action potential duration and transiently the force of contraction.…”

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confidence: 99%

Endogenous muscarinic activity attenuates adrenergic inotropic effects in field stimulated atrial myocardium from children with congenital heart defects

Borthne¹,

Langslet²,

Lindberg

et al. 1999

Acta Physiologica Scandinavica

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To analyse the possible influence of endogenous muscarinic activity on the inotropic effects of endogenously released noradrenaline in field stimulated myocardial preparations from atria of children with congenital heart defects, we studied the maximal effect of the muscarinic antagonist atropine (1.5 micromol L(-1)). Maximal force of contraction increased by 12.8 +/- 2.0% (SEM), while the maximal rate of development of the force increased by 16.7 +/- 2.7% (SEM). Time to half maximal developed force was 57 +/- 5 s (SEM). Time to peak force, time to relax to the 20% level and relaxation time all decreased significantly after atropine. Compared with endogenous adrenoceptor stimulation alone, the combined effects of partial muscarinic and adrenergic receptor stimulation thus were moderate reductions of the maximal force of contraction and maximal rate of development of the force and increased time to peak force, time to relax to the 20% level and relaxation time. The main effect of the endogenous muscarinic activity probably was to attenuate the effect of the beta-adrenoceptor stimulation. The endogenous muscarinic activity in field stimulated atrial preparations from children is significant, and has to be taken into account in experimental set-ups.

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Functional role of cholinoceptors and purinoceptors in human isolated atrial and ventricular heart muscle

Cited by 31 publications

References 25 publications

Mechanically Induced Potentials in Fibroblasts from Human Right Atrium

Mechanically Induced Potentials in Fibroblasts from Human Right Atrium

K⁺current changes account for the rate dependence of the action potential in the human atrial myocyte

Endogenous muscarinic activity attenuates adrenergic inotropic effects in field stimulated atrial myocardium from children with congenital heart defects

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Functional role of cholinoceptors and purinoceptors in human isolated atrial and ventricular heart muscle

Cited by 31 publications

References 25 publications

Mechanically Induced Potentials in Fibroblasts from Human Right Atrium

Mechanically Induced Potentials in Fibroblasts from Human Right Atrium

K+current changes account for the rate dependence of the action potential in the human atrial myocyte

Endogenous muscarinic activity attenuates adrenergic inotropic effects in field stimulated atrial myocardium from children with congenital heart defects

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K⁺current changes account for the rate dependence of the action potential in the human atrial myocyte