Effects of Gap Junction Conductance in Synchronizing Cardiac Oscillators

The auto-rhythmic cells in the Rabbit heart beat at a wide range of frequencies (330-80 beats per minute) in culture, but in the whole heart they beat at a common frequency set by the normal sinus rhythm. For such a varied range of intrinsic frequencies in a large network of oscillators synchronization becomes much more difficult. Keeping this in mind, an attempt has been made with the help of electro physiology model of cardiac pacemaker cells to analyze the synchronization issue in the syncytium of the cardiac system. A single cell model of a rabbit sinoatrial node was simulated using Matlab package and it was found that the simulated results matched with the experimental findings. Being a sinoatrial nodal cell there exist a parameter for varying the frequency of the generated action potential. After a thorough study of the single cell model, cells were coupled via a coupling element that resembles Gap Junction conductance in real electrophysiology, thus a pair of cell is developed. The intrinsic frequencies of the cells were varied to all possible extents and it was observed that the cells were oscillating in a new frequency and thereby failed to synchronize. The significant role of gap junctions in establishing synchronization was carried out. These investigations emphasized the role of gap junction conductance in their role in synchronization.