title: Combined electric field and gap junctions on propagation of action potentials in cardiac muscle and smooth muscle in PSpice simulation.
abstract: Propagation of action potentials in cardiac muscle and smooth muscle were simulated using the PSpice program. Excitation was transmitted from cell to cell along a strand of 6 cells (cardiac muscle) or 10 cells (smooth muscle) either not connected (control) or connected by low-resistance tunnels (gap-junction connexons). A significant negative cleft potential (V(jv) ) develops in the narrow junctional cleft when the pre-JM fires. V(jc) depolarizes the postjunctional membrane (post-JM) to threshold by a patch-clamp action. With few connecting tunnels, cell-to-cell transmission by the EF mechanism was facilitated. With many tunnels, propagation was dominated by the low-resistance mechanism, and propagation velocity (theta) became very fast and nonphysiological. In conclusion, when the 2 mechanisms for cell-to-cell transfer of excitation were combined, the two mechanisms facilitated each other in a synergistic manner. When there were many connecting tunnels, the tunnel mechanism was dominant.
authors.affiliation: Department of Molecular & Cellular Physiology, University of Cincinnati College of Medicine, OH 45267-0576, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Sperelakis
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D002450:Cell Communication / Q000502:physiology; D003198:Computer Simulation; D004553:Electric Conductivity; D017097:Electric Impedance; D004558:Electric Stimulation; D004574:Electromagnetic Fields; D017629:Gap Junctions / Q000502:physiology*; D006329:Heart Conduction System / Q000502:physiology; D006801:Humans; D008955:Models, Cardiovascular; D009130:Muscle, Smooth / Q000166:cytology* / Q000502:physiology; D009206:Myocardium / Q000737:chemistry / Q000166:cytology*; D013997:Time Factors; D014655:Vascular Resistance / Q000502:physiology