Role of Ca2+ in maintenance of rabbit myocardial cell membrane structural and functional integrity

Crevey, Barry J.; Langer, G. A.; Frank, Joy S.

doi:10.1016/0022-2828(78)90354-1

Cited by 82 publications

(8 citation statements)

References 26 publications

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“…However, the time of perfusion should be limited to a few minutes, normally 3–5, to avoid the phenomenon of ‘Ca 2+ paradox’ [17, 18]. The enzymes used for digestion are dissolved in low Ca 2+ solution, although some Ca 2+ may be necessary to allow for adequate enzyme activity.…”

Section: Cardiomyocyte Isolationmentioning

confidence: 99%

Methods in cardiomyocyte isolation, culture, and gene transfer

Louch

Sheehan

Wolska

2011

Journal of Molecular and Cellular Cardiology

423

396

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Since techniques for cardiomyocyte isolation were first developed nearly 35 years ago, experiments on single myocytes have yielded great insight into their cellular and sub-cellular physiology. These studies have employed a broad range of techniques including electrophysiology, calcium imaging, cell mechanics, immunohistochemistry and protein biochemistry. More recently, techniques for cardiomyocyte culture have gained additional importance with the advent of gene transfer technology. While such studies require a high quality cardiomyocyte population, successful cell isolation and maintenance during culture remain challenging. In this review, we describe methods for the isolation of adult and neonatal ventricular myocytes from rat and mouse heart. This discussion outlines general principles for the beginner, but also provides detailed specific protocols and advice for common caveats. We additionally review methods for short-term myocyte culture, with particular attention given to the importance of substrate and media selection, and describe time-dependent alterations in myocyte physiology that should be anticipated. Gene transfer techniques for neonatal and adult cardiomyocytes are also reviewed, including methods for transfection (liposome, electroporation) and viral-based gene delivery.

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Section: Cardiomyocyte Isolationmentioning

confidence: 99%

Methods in cardiomyocyte isolation, culture, and gene transfer

Louch

Sheehan

Wolska

2011

Journal of Molecular and Cellular Cardiology

423

396

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“…This increase may be a direct effect of removing Ca from control sites on the membrane or might be secondary to depolarization, which has been observed in taeni coli (Builbring & Tomita, 1970). Several studies have shown that Mg is able to substitute for Ca as a membrane 'stabilizer' (Frankenhaeuser & Hodgkin, 1957;Biulbring & Tomita, 1977;Crevey et al 1978;Martin & Gordon, 1983) and also prevents the depolarizing effect of Ca removal (Bulbring & Tomita, 1970). We found that the increase in basal 42K efflux during Ca removal was suppressed in a concentration-dependent manner by Mg, as was the NA-stimulated increase in 42K efflux.…”

Section: Discussionmentioning

confidence: 99%

“…There is extensive evidence that Mg can substitute for Ca in the maintenance of stable membrane behaviour of excitable tissues (Frankenhaeuser & Hodgkin, 1957;Billbring & Tomita, 1977;Crevey, Langer & Frank, 1978 [Mg] were 1-0 mm (@, n = 5), 4-3 mm (U n = 4), 8-9 mm (A, n = 4), 13-7 mm (*, n = 5) and 18-6 mm (x, n = 4). NA, 10-5 M.…”

Section: Effect Of Ca Removalmentioning

confidence: 99%

Calcium regulation of potassium fluxes in rabbit aorta during activation by noradrenaline or high potassium medium.

Aaronson¹,

Jones²

1985

The Journal of Physiology

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SUMMARY1. The dependency of noradrenaline-and depolarization-mediated increases in K permeability on cellular Ca was investigated by measuring the effect of diltiazem and Ca-free medium on stimulated 42K efflux and contracture.2. The increase in the rate constant (k) for 42K efflux induced by cellular depolarization with 80 mM-K was inhibited by 70 % in the presence of 10-5 M-diltiazem. The noradrenaline (NA)-mediated increase in k was only slightly suppressed by diltiazem at 10-5 M-NA, but was inhibited by diltiazem in a dose-dependent fashion for a submaximal concentration of NA 10-7 M. Similar inhibitory effects were observed on contractile responses. 3. Basal 42K efflux progressively increased in a 0 Ca physiological salt solution (PSS) containing 2 mM-EGTA. This process was suppressed in a concentrationdependent manner as [Mg] was increased. In experiments utilizing 0 Ca PSS, [Mg] was therefore raised to 15 mm to maintain stable basal effluxes.4. Ca removal for 30 min reduced the 80 mM-K-mediated increase in k by 64 %.The NA-induced increase in k became more transient in 0 Ca PSS with a progressive diminution in the magnitude of this response as the duration of Ca depletion was increased. The diminution of the 42K efflux response in 0 Ca PSS was well fitted by a mono-exponential function (half-time, t1 = 46 min). The NA-induced contracture in 0 Ca solution decreased with a biphasic time course subsequent to Ca removal.5. Intracellular Ca release by NA, measured by means of a 45Ca efflux protocol, decreased as a mono-exponential function of time, with a to of 21 min.6. We conclude that both a-receptor activation and membrane depolarization increase K permeability largely as a result of increased cellular free [Ca]. The effect ofdepolarization appears to depend mainly on influx of extracellular Ca. NA increases both influx and intracellular release of Ca which serve to open K channels. The apparent release of cellular Ca as measured by 45Ca efflux into Ca-free solution decreased more rapidly, however, than did the NA stimulation of 42K efflux and tension. These observations may result from the presence of a slowly depleted Ca store which cannot be detected directly by measuring NA-induced release of 45Ca.

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“…Isolated cardiac single cells that tolerate a millimolar range of external Ca (Powell & Twist, 1976;Isenberg & Klockner, 1980) yield a suitable preparation with the shortest possible diffusion time for studies of cardiac muscle. However, enzymatic digestion may possibly affect excitation-contraction coupling (Crevey, Langer & Frank, 1978) and ionic binding to the surface membrane (Lee, Akaike & Brown, 1977;Brown, Lee & Powell, 1981), and the measurement of tension developed by single cells is technically difficult (Brady, Tan & Ricchiuti, 1979;Fabiato, 1981). Therefore, these issues have been re-examined in the present study by determining the effect of changes in extracellular Ca concentration on very thin, mechanically isolated preparations of guinea-pig right ventricles.…”

Section: Introductionmentioning

confidence: 99%

Effect of extracellular calcium on contractile activation in guinea‐pig ventricular muscle.

Kitazawa¹

1984

The Journal of Physiology

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SUMMARY1. The problem of whether or not the alterations in twitch tension of mammalian cardiac muscle induced by changes in extracellular Ca concentration ([Ca].) are due to the Na-Ca exchange process across the surface membrane and/or the changes in the amount of Ca in the sarcoplasmic reticulum has been re-examined by using thin bundles (70-120 ,sm diameter) dissected from guinea-pig papillary muscle.2. The observed time course ofthe change in the twitch tension due to a step change in [Ca]o was compared with that computed on a basis of the diffusion process of Ca ions in a circular cylinder and of the steady-state relation between [Ca]. and twitch tension.3. After a sudden decrease in [Ca]. from 2 mm to various lower concentrations, the isometric twitch tension of the thin bundles first fell rapidly and monotonically and then showed a much smaller and slower secondary fall. The correspondence of the observed time course of the rapid phase with the predicted time course and the observed half-time of the rapid phase ranging from 1-0 to 2-5 s indicate that the rapidity of the twitch response may be dominated by simple diffusion of Ca ions through the extracellular space. If so, the effective diffusion constant of Ca ions inside the bundles was 1-4+002 x 10-6 cm2/S (mean+s.E., n = 9). 4. The magnitude and direction of the step change in [Ca]0 or the change at different stimulus frequencies gave rise to dissimilar time courses of the contractile change; the difference in the rapid time courses due to these factors could be explained by the simple diffusion models, but not in the much slower phase.5. The half-time for the Ca effect was the same as that for the rapid effect of Na ions in the external solutions.6. The time course of twitch decline due to [Ca]0 decrease in the Na-free (Li) solution was identical to that predicted from the time course measured in the Na-rich solution and the steady-state relation between [Ca]0 and tension in the Na-free solution.7. The half-time of Ca leak from the sarcoplasmic reticulum in the skinned cardiac muscle was 40-60 s in the presence of 10 mM-EGTA, much shorter than that of the

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Role of Ca2+ in maintenance of rabbit myocardial cell membrane structural and functional integrity

Cited by 82 publications

References 26 publications

Methods in cardiomyocyte isolation, culture, and gene transfer

Methods in cardiomyocyte isolation, culture, and gene transfer

Calcium regulation of potassium fluxes in rabbit aorta during activation by noradrenaline or high potassium medium.

Effect of extracellular calcium on contractile activation in guinea‐pig ventricular muscle.

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