Vascular responsiveness to atriopeptin iii in mineralocorticoid hypertensive rats

Loren P. Thompson, R Clinton Webb

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Atrial natriuretic factor may play a physiological role in sodium and water balance because of its potent vasoactive, diuretic, and natriuretic properties. The goal of this study was to characterize vasoactive properties of a synthetic atriai peptide (atriopeptin III) in mineralocorticoid hypertensive rats. Rats were uninephrectomized, given silastic implants with deoxycorticosterone acetate (200 mg/kg), and maintained on 1% NaCl/0.2% KC1 drinking water. Four to five weeks after implant, aortae were removed and cut into helical strips, which were mounted in organ chambers for measurement of isometric contractile force. Following contraction to norepinephrine (5.9 x 10-8 M), cumulative addition of atriopeptin III (10-11-10-7 M) to the organ chamber caused relaxation of aortic segments. The response was concentration related, and hypertensive aortae did not differ significantly from normotensive aortae in relaxation magnitude. The rate of relaxation to atriopeptin m was slower in aortae from hypertensive rats. Aortic strips treated with atriopeptin III (but not sodium nitroprusside) showed reduced norepinephrine responsiveness after washout of the peptide from the organ chamber. This aftereffect of atriopeptin III did not occur in strips contracted with serotonin or KC1. The aftereffect was significantly less in hypertensive aortae. These results indicate: 1) the magnitude of atriopeptin Ill-induced relaxation in hypertensive aortae does not differ from control values; 2) the rate of relaxation to the peptide is slower in hypertensive aortae; and 3) atriopeptin III has an aftereffect, which is less in hypertensive aortic strips. We conclude that atriopeptin III causes an inhibitory aftereffect on norepinephrine-induced contractions of aortae that is mediated through cellular mechanisms distinct from its direct relaxant effect.

Original languageEnglish (US)
Pages (from-to)146-150
Number of pages5
JournalHypertension
Volume8
Issue number4
StatePublished - Jan 1 1986
Externally publishedYes

Keywords

  • Aortic strips
  • Atrial natriuretic factor
  • Deoxycorticosterone acetate hypertensive rats
  • KCI
  • Norepinephrine
  • Serotonin
  • Vascular responsiveness

ASJC Scopus subject areas

  • Internal Medicine

Fingerprint Dive into the research topics of 'Vascular responsiveness to atriopeptin iii in mineralocorticoid hypertensive rats'. Together they form a unique fingerprint.

Cite this