Pacemaker synchronization of electrically coupled rabbit sinoatrial node cells

• Published in: The Journal of general physiology 1998-01, Vol.111 (1), p.95-112
• Main Authors: Verheijck, E E, Wilders, R, Joyner, R W, Golod, D A, Kumar, R, Jongsma, H J, Bouman, L N, van Ginneken, A C
• Format: Article
• Language: English
• Subjects: Action Potentials - physiology; Anatomy & physiology; Animals; Biological Clocks - physiology; Cellular biology; Electric Conductivity; Female; Gap Junctions - physiology; Heart; Ions; Male; Muscle Fibers, Skeletal - physiology; Neurology; Patch-Clamp Techniques; Rabbits; Sinoatrial Node - cytology; Sinoatrial Node - physiology
• ISSN: 0022-1295; 1540-7748
• DOI: 10.1085/jgp.111.1.95

The effects of intercellular coupling conductance on the activity of two electrically coupled isolated rabbit sinoatrial nodal cells were investigated. A computer-controlled version of the "coupling clamp" technique was used in which isolated sinoatrial nodal cells, not physically in contact with each other, were electrically coupled at various values of ohmic coupling conductance, mimicking the effects of mutual interaction by electrical coupling through gap junctional channels. We demonstrate the existence of four types of electrical behavior of coupled spontaneously active cells. As the coupling conductance is progressively increased, the cells exhibit: (a) independent pacemaking at low coupling conductances, (b) complex dynamics of activity with mutual interactions, (c) entrainment of action potential frequency at a 1:1 ratio with different action potential waveforms, and (d) entrainment of action potentials at the same frequency of activation and virtually identical action potential waveforms. The critical value of coupling conductance required for 1:1 frequency entrainment was