VEGA 2/0203/11

Principal Investigator: Ivan Zahradník

Duration: January 2011 – December 2013
Coordinating Organization: Institute of Molecular Physiology and Genetics SAS, Bratislava

Annotation:

The sarcolemma of cardiomyocytes represents a complex system, composed of lipids, proteins and membrane
cytoskeleton, which forms functional clusters, caveolae, t-tubules and intercellular contacts. In contrast to nerve and secretory cells, the understanding of membrane dynamics of cardiomyocytes is missing, despite its importance in regulation of their physiological functions. Previously, we have developed an exact method for measuring electrical parameters of cardiomyocytes. Here, we utilize the Q-method to portrait the sarcolemmal dynamics in cardiomyocytes by measuring fluctuations of capacitance and conductance, and by analysis of their temporal, correlational, frequency and fractal representations. The data will be interpreted by mathematical modeling. New knowledge on sarcolemmal dynamics of cardiac myocyte will complement the existing picture of cell membrane dynamics and form the basis for studies related to the variability of excitability and contractility and to pathology of heart rhythm.

Keywords:

Animal physiology; biophysics; heart muscle; cellular membrane dynamics; electrical parameters; fluctuation analysis;

Objectives:

The objective of the project is to obtain basic information on cell membrane dynamics. The results will enable to determine the relationship between membrane transport proteins and functional structure of the surface membrane of cardiac myocytes. We suppose that the comparative analysis of electrical parameters of isolated cardiac myocytes will enable to determine:

• Short-term dynamics of the sarcolemma as measured by membrane capacitance.
• The relationship between variation of membrane capacitance and variation of the activity of basic types of ion transport proteins, as measured by the correlation between membrane capacitance and membrane conductance.
• The contribution of basic types of membrane conductance to the basal electrical activity of cardiac myocytes, as measured by spectral and fractal analysis in the temporal and frequency domains.

Publications: