It has been hypothesized that the pathophysiology of chronic heart failure (CHF) may be due to a relative deficiency of atrial natriuretic factor (ANF) and/or blunted responsiveness to ANF in this state. The work presented in this thesis evaluates the role of ANF in rats with chronic moderate high-output heart failure by (1) characterizing plasma and tissue ANF levels, hemodynamics and renal function at different stages of the development of heart failure; (2) assessing the contribution of the atria and ventricles to plasma ANF levels; and (3) investigating the role of ANF and renin-angiotensin systems (RAS) in rats with aorto-caval (A-C) shunts. / Chronically increased cardiac filling pressure stimulated not only ANF release but also ANF synthesis in each cardiac chamber. This in turn contributed to elevated plasma ANF levels in A-C shunt rats. An attenuated renal response to endogenous ANF and sodium and water retention were apparent in A-C shunt rats. Under inhibition of RAS, plasma ANF may exert its actions more effectively. Thus, chronic ACE inhibition and ANG II receptor antagonism improved hemodynamic conditions, diminished water retention, reversed cardiac hypertrophy, and restored plasma and tissue ANF to more "normal" levels in rats with moderate high-output heart failure. / Taken together, elevated plasma ANF levels may play an important role in maintaining hemodynamic and body fluid homeostasis by opposing the neurohormonal vasoconstrictor systems in A-C shunt rats. However, a relative deficiency of plasma ANF and/or an attenuated response to endogenous ANF, mediated by activated neurohormonal vasoconstrictor systems, may contribute to the pathophysiology and development of heart failure at different stages. (Abstract shortened by UMI.)
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.69541 |
| Date | January 1992 |
| Creators | Qing, Gefei |
| Contributors | Garcia, Raul (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 | Master of Science (Division of Experimental Medicine.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001319508, proquestno: AAIMM87841, Theses scanned by UMI/ProQuest. |
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