Electrotonic spread of current in monolayer cultures of neonatal rat heart cells

Jongsma, Habo J.; Rijn, Henny E. Van

doi:10.1007/bf01868061

Cited by 73 publications

(43 citation statements)

References 34 publications

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“…When dissociated embryonic or neonatal ventricular myocytes are grown in monolayer culture they display synchronous beating (Crill, Rumery & Woodbury, 1959;Harary & Farley, 1963), which has been demonstrated to be the result of electrical coupling mediated by low resistance junctions between myocytes ( M -M junctions), between myocytes and fibroblasts (M-F junctions) and between fibroblasts (F-F junctions) (Crill et al, 1959;Goshima, 1969, Hyde et al, 1969Jongsma & van Rijn, 1972;Sachs, 1976). In this study, it has been shown that under normal ionic conditions both M -M and M -F junctions will also allow the transfer of the dye Lucifer Yellow CH (mol wt 457).…”

Section: Discussionmentioning

confidence: 99%

Permeability and structural studies of heart cell gap junctions under normal and altered ionic conditions

1982

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Summary.The permeability and ultrastructure of communicating junctions of cultured neonatal rat ventricular cells are examined under control conditions and during treatments which raise intracellular Ca 2+. Lucifer Yellow (487mol wt) is used to examine junctional permeability. Under normal ionic conditions dye transfer from an injected muscle cell to neighboring muscle cells occurs rapidly (in less than 6 sec) while transfer to neighboring fibroblasts occurs more slowly. Application of monensin, which results in a partial contracture with superimposed asynchrony, or A23187, which results in a partial contracture, do not inhibit the transfer of dye between the muscIe cells. A23187 did result in junctional blockade between muscle cells and fibroblasts. Freezefractured gap junctions from control and monensin-treated cells exhibit no distinguishable differences. Center-to-center spacing was not significantly different, 9.0 nm_+ 1.4 SD versus 9.2 rim+ 1.3 SD, respectively; and particle diameters were virtually unchanged, 8.69 nm+0.9 sD versus 8.61 nm• 1.07 SD, respectively. These results suggest that concentrations of intracellular Ca 2 + sufficient to support a partial contracture and asynchronous contractile activity do not result in a block of intercellular junctions in cultured myocardial cells. These results are discussed in terms of intracelhilar Ca; +-buffering and junctional sensitivity to Ca 2 +.

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Section: Discussionmentioning

confidence: 99%

Permeability and structural studies of heart cell gap junctions under normal and altered ionic conditions

1982

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“…Muhicellular, sheet-like preparations ot tissue-cultured cardiac muscle suffer from the same drawbacks as their naturally occurring counterparts: problems arising from the complex geometry of fiber interconnections. These preparations have been treated theoretically as a one-dimensional cell (flat ribbon or cylinder [47,48,51,62]) although perhaps, in some cases, the assembled clusters of myoblasts right have been better described as a thick, plane cell or semi-infinite solid. In addition, such tissue-cultured preparations generally were "contaminated" with nonmuscle cells, and, to further complicate matters, the single-electrode bridge technique was frequently used in some of these studies in a way that was open to the kind of criticism referred to above.…”

Section: Discussionmentioning

confidence: 99%

“…The previously reported values for C,~ vary widely both for naturally occurring cardiac muscle (0.81-13.3 #F.cm -2 [2,3,39,46,50]) and tissuecultured heart cells (1.3-20 #F .cm -2 [48,51]), no doubt for the same reasons mentioned for the equivalently wide variations in R,,. Furthermore, the area of membrane per unit length of the preparations used in these reports may have been in two components, one being in series with a resistance; as a consequence, c,, should vary with the method (e.g.…”

Section: Membrane Capacitancementioning

confidence: 92%

“…In contrast, for cardiac muscle values ot R~ ranging from 60 to 500 tlcm have been reported for naturally occurring (2,3,39,46) as well as tissue-cultured preparations (47,48). This large spread is without doubt largely attributable to the varying degree to which the actual geometry of the preparation approached the various simple geometries (cylinder, sheet, etc.)…”

Section: Myoplasmic Resistancementioning

confidence: 95%

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A synthetic strand of cardiac muscle: its passive electrical properties.

Lieberman¹,

Sawanobori²,

Kootsey³

et al. 1975

The Journal of General Physiology

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A B S T R n O T The passive electrical properties of synthetic strands of cardiac muscle, grown in tissue culture, were studied using two intraeeUular microelectrodes: one to inject a rectangular pulse of current and the other to record the resultant displacement of membrane potential at various distances from the current source. In all preparations, the potential displacement, instead of approaching a steady value as would be expected for a cell with constant electrical properties, increased slowly with time throughout the current step. In such circumstances, the specific electrical constants for the membrane and cytoplasm must not be obtained by applying the usual methods, which are based on the analytical solution of the partial differential equation describing a one-dimensional cell with constant electrical properties. A satisfactory fit of the potential waveforms was, however, obtained with numerical solutions of a modified form of this equation in which the membrane resistance increased linearly with time. Best fits of the waveforms from 12 preparations gave the foUowing values for the membrane resistance times unit length, membrane capacitance per unit length, and for the myoplasmic resistance: 1.22 4-0.13 X 10 ~ f~cm, 0.224 4-0.023 # F . c m -x, and 1.37 -4-0.13 X 107 ~crn -t, respectively. The value of membrane capacitance per unit length was close to that obtained from the time constant of the foot of the action potential and was in keeping with the generally satisfactory fit of the recorded waveforms with solutions of the cable equation in which the membrane impedance is that of a single capacitor and resistor in parallel. The area of membrane per unit length and the cross-sectional area of myoplasm at any given length of the preparation were determined from light and composite electron micrographs, and these were used to calculate the foUowing values for the specific electrical membrane resistance, membrane capacitance, and the resistivity of the cytoplasm: 20.5 + 3.0 )< 103 ftcm z, 1.54 4-0.24 #F.cm-", and 180 -4-34 ~cm, respectively. I N T R O D U C T I O NIn cardiac muscle, as in other excitable cells, the passive electrical properties of the cell m e m b r a n e a n d cytoplasm must be d e t e r m i n e d from observations of

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“…Electrophysiological readouts of cellular voltage can be obtained by microelectodes (Jongsma and van Rijn, 1972), multielectrode arrays (Israel et al, 1990), or optical mapping (Fast and Kleber, 1993;Rohr and Salzberg, 1994). Optical mapping makes possible the simultaneous measurement of action potentials from a large number of recording sites, which can be used to generate maps of electrical propagation.…”

Section: Introductionmentioning

confidence: 99%

Cell cultures as models of cardiac mechanoelectric feedback

Zhang

Sekar

McCulloch

et al. 2008

Progress in Biophysics and Molecular Biology

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Although stretch-activated currents have been extensively studied in isolated cells and intact hearts in the context of mechanoelectric feedback (MEF) in the heart, quantitative data regarding other mechanical parameters such as pressure, shear, bending, etc, are still lacking at the multicellular level. Cultured cardiac cell monolayers have been used increasingly in the past decade as an in vitro model for the studies of fundamental mechanisms that underlie normal and pathological electrophysiology at the tissue level. Optical mapping makes possible multisite recording and analysis of action potentials and wavefront propagation, suitable for monitoring the electrophysiological activity of the cardiac cell monolayer under a wide variety of controlled mechanical conditions. In this paper, we review methodologies that have been developed or could be used to mechanically perturb cell monolayers, and present some new results on the acute effects of pressure, shear stress and anisotropic strain on cultured neonatal rat ventricular myocyte (NRVM) monolayers.

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Electrotonic spread of current in monolayer cultures of neonatal rat heart cells

Cited by 73 publications

References 34 publications

Permeability and structural studies of heart cell gap junctions under normal and altered ionic conditions

Permeability and structural studies of heart cell gap junctions under normal and altered ionic conditions

A synthetic strand of cardiac muscle: its passive electrical properties.

Cell cultures as models of cardiac mechanoelectric feedback

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