Chaos in weakly-coupled pacemaker cells.
A model of the rabbit sinoatrial action potential is introduced, based on a model by Morris & Lecar. One cell is described by two nonlinear first-order ordinary differential equations, with ten constant parameters. The model is much simpler than most other models in use, but can reproduce perfectly experimentally recorded action potentials. The dynamics of two coupled cells, with and without the presence of periodic acetylcholine pulses, shows examples of bifurcations and strange attractors, mathematical phenomena characterizing chaotic motion. It remains to be clarified whether such dynamics is actually observed, for example in the small irregular variations of the normal heart rate.
Endresen
L P
LP
Department of Physics, Norwegian University of Science and Technology, Trondheim, Norway.
D000109:Acetylcholine / Q000502:physiology; D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D003198:Computer Simulation; D008955:Models, Cardiovascular; D017711:Nonlinear Dynamics; D011817:Rabbits; D012849:Sinoatrial Node / Q000502:physiology*; D013268:Stimulation, Chemical; D014630:Vagus Nerve / Q000502:physiology
D000109:Acetylcholine