Reversible method for assessment of tubular membrane capacitance in cardiomyocytes
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| Year of publication | 2018 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Transverse-axial tubular system (TATS) plays a key role in the cardiac cell function. Some cardiac diseases (e.g. heart failure) lead to structural and functional changes in TATS. Among others, the membrane capacitance of TATS may be altered. The TATS and surface membranes are closely interconnected and traditional methods of assessment of the cell membrane capacitance not able to distinguish them. Hence, the capacitance of TATS has been determined mainly by using technique called detubulation which is, however, irreversible and shows several important limitations. We have recently developed a new method for estimation of TATS capacitance in isolated cardiomyocytes that is fully reversible. The method is based on electrical separation of the surface and TATS membranes. It uses short applications of isotonic sucrose (IS) solution which leads to a significant increase of the electric resistance of TATS. The electrical parameters of the two membrane systems could be then analysed separately. After application of IS solution, its diffusion into TATS lead to transient changes in the membrane current and potential. These changes were well reproduced by model simulations. Capacities of TATS and surface membranes were determined from approximation of the current responses by a sum of two exponential functions. Several criteria for selection of reliable data were looked for and defined. Based on the data and their subsequent analysis, we conclude that the fractional value of TATS capacitance in adult rat ventricular myocytes is ~0.43 on average. |
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