gms | German Medical Science

29. Wissenschaftlicher Kongress der Deutschen Hochdruckliga

Deutsche Hochdruckliga e. V. DHL ® - Deutsche Hypertonie Gesellschaft Deutsches Kompetenzzentrum Bluthochdruck

23. bis 25.11.2005, Berlin

Neonatal sympathectomy reduces renal NADPH oxidase activity and shifts the pressure natriuresis relationship to lower arterial pressure in spontaneously hypertensive rats (SHR)

Neonatale Sympathektomie vermindert bei spontan hypertensiven Ratten (SHR) die renal NADPH Oxidase Aktivität und verschiebt die Druck-Natriurese-Kurve zu niedrigeren Perfusionsdrücken

Meeting Abstract

  • O. Grisk - Universität Greifswald, Karlsburg (Karslburg, D)
  • T. Schlüter - Universität Greifswald, Karlsburg (Karslburg, D)
  • A. Steinbach - Universität Greifswald, Karlsburg (Karslburg, D)
  • G. Lorenz - Universität Greifswald, Karlsburg (Karslburg, D)
  • R. Rettig - Universität Greifswald, Karlsburg (Karslburg, D)

Hypertonie 2005. 29. Wissenschaftlicher Kongress der Deutschen Hochdruckliga. Berlin, 23.-25.11.2005. Düsseldorf, Köln: German Medical Science; 2006. Doc05hochP95

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/hoch2005/05hoch095.shtml

Veröffentlicht: 8. August 2006

© 2006 Grisk et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

The kidney contributes to the sympathectomy-induced arterial pressure reduction in SHR. We investigated the effects of neonatal sympathectomy on renal NADPH oxidase expression and enzyme activity as well as on renal hemodynamics and sodium excretion in SHR. Renal cortical mRNA expression of NADPH oxidase subunits was not affected by sympathectomy while renal medullary mRNA expression of NADPH oxidase subunits p47phox and gp91phox was 40% less in sympathectomized vs. hydralazine-treated controls (p < 0.001, n = 9 per group). After salt loading, medullary mRNA expression of p47phox and gp91phox was 25 % less in sympathectomized than in hydralazine-pretreated SHR (p < 0.01, n = 7 per group). Sympathectomized animals had lower cortical (-50%, p < 0.001) and medullary (-30%, p < 0.05) NADPH oxidase activity than hydralazine-treated and untreated SHR. Histology excluded differential leukocyte infiltration as a cause of different NADPH oxidase mRNA expression levels and activities. To study renal hemodynamics and pressure natriuresis in a comparable neurhumoral environment, kidneys were transplanted from sympathectomized and hydralazine-treated donors into untreated SHR (n = 7 per group). GFR, RBF, medullary blood flow and fractional Na+ excretion were similar under baseline conditions. Renal vascular resistance was lower and the pressure natriuresis curve was shifted to lower perfusion pressure by 15-20 mmHg (p < 0.05) in kidneys from sympathectomized donors. No changes in renal medullary flow in response to arterial pressure forcing were observed in either group. In addition, the pressure natriuresis curve was steeper in kidneys from sympathectomized rats. Neonatal sympathectomy reduces renal NADPH oxidase activity with differential effects on renal cortical and medullary NADPH oxidase mRNA expression in SHR. Chronically reduced NADPH oxidase activity may induce alterations in vascular and tubular function which finally lead to a leftward shift and increased slope of the pressure natriuresis curve in SHR kidneys!