AT1 receptors mediate chronic central nervous system AII hypertension in rats fed high sodium chloride diet from weaning

Amadou K.S. Camara, Jeffrey L. Osborn

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13 Scopus citations

Abstract

CNS angiotensin II (AII) hypertension is induced by chronic, low dose intracerebroventricular (ICV) AII infusion only in rats raised on a relatively high sodium chloride diet (250 meq kg-1 food) from weaning. This experimental model of hypertension is dependent upon renal sympathetic innervation and associated with neurogenic sodium retention. This study determined whether AT1 and/or AT2 receptor subtypes in the CNS mediate this neurogenic ICV AII hypertension. Rats were weaned at 21 days of age and fed a 1.5% sodium chloride diet for 10-12 weeks. At adulthood, animals were instrumented with CNS lateral ventricular cannulas, femoral arterial and vein catheters and housed in metabolic pens for chronic study. Low dose ICV AII infusion (20 ng min-1) increased mean arterial pressure by 12±2 mm Hg and decreased urinary sodium excretion for three consecutive days. Subsequent ICV AT1 blockade with losartan abolished both the pressor and antinatriuretic responses to low dose ICV AII. In contrast, ICV AT2 receptor blockade with PD 123319 did not affect either angiotensin induced pressor or antinatriuretic responses. Following cessation of ICV AII infusion, arterial pressure and sodium excretion returned to values not significantly different from control in both groups of rats. These data confirm that low dose ICV AII causes hypertension and sodium retention in rats raised from early age on moderately elevated sodium intakes. This AII mediated neurogenic hypertension and antinatriuresis is transduced by activation of CNS AT1 receptors and not by activation of central AT2 receptors. Copyright (C) 1998 Elsevier Science B.V.

Original languageEnglish
Pages (from-to)16-23
Number of pages8
JournalJournal of the Autonomic Nervous System
Volume72
Issue number1
DOIs
StatePublished - Aug 6 1998

Bibliographical note

Funding Information:
We gratefully acknowledge the generous gifts of losartan by the Merck Dupont and that of PD 123319 by Parke-Davis. The authors wish to thank Mr Erez Gordin for his technical and computer assistance. We would also like to extend our appreciation to the following individuals for their technical assistance: Ms Terry Kurth, Mr Harold Eick and Mr David Eick. This work was supported in part by an NIH Minority Graduate Assistant Supplement and by NHLBI PO1-29587 and NHLBI RO1-40137. Address reprint requests to Dr Jeffrey L. Osborn, Department of Physiology, Medical College of Wisconsin, Milwaukee, WI.

Keywords

  • Angiotensin receptors
  • Central nervous system
  • Hypertension
  • Kidney function
  • Sodium chloride intake
  • Sympathetic nerves

ASJC Scopus subject areas

  • General Neuroscience
  • Physiology
  • Clinical Neurology

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