The excitability properties of multicellular and single cellular cardiac pacemaking tissues was examined using mathematical, electrophysiological and molecular biological techniques. Particular attention was focused on identifying the different ionic channels that control the excitability of a physiological pacemaker, the rabbit atrioventricular node. The first part of the study centers on the excitability and rhythmicity of rabbit atrioventricular cell clusters and embryonic chick heart cell aggregates to compare cardiac pacemaking tissues showing slow- and fast-type action potentials. Subsequent experiments examined the membrane excitability properties of single isolated atrioventricular nodal cells and characterized the principle ionic currents that govern excitability. One of these channels that is directly gated by cyclic nucleotides, the "pacemaker" channel (If), was found to be non-uniformly expressed in different populations of AV nodal cells. The final part of the thesis involved a molecular characterization of cyclic nucleotide-gated ion channel subunits expressed in cardiac tissue during embryonic development. The relationship of these channels to the cardiac "pacemaker" channel (If) and their possible role in controlling cardiac excitability were considered.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.37525 |
| Date | January 1997 |
| Creators | Munk, Andrew A. |
| Contributors | Shrier, Alvin (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Physiology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001601635, proquestno: NQ44527, Theses scanned by UMI/ProQuest. |
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