Chronic effects of rat atrial natriuretic polypeptide (ANP) on blood pressure and sodium-water excretion in angiotensin II- and vasopressin-infused rats

Masahiro Kohzuki, Keishi Abe, Minoru Yasujima, Masaya Tanno, Yutaka Kasai, K. Omata, Makito Sato, Masao Hiwatari, K. Kudo, Kazuhisa Takeuchi, Masayuki Kanazawa, Kaoru Yoshinaga

Research output: Contribution to journalArticlepeer-review

Abstract

To assess the pathophysiological role of atrial natriuretic polypeptide (ANP) in the regulation of blood pressure, we studied the effect of chronic infusion of synthetic rat-ANP on blood pressure and sodium-water excretion in angiotensin II (A II) -and vasopressin (VP)-infused rats on regular intakes of sodium or on sodium loading with 1% NaCl as a drinking water. When subdepressor dose (150 μg/kg/day) of ANP was infused into the jugular vein by an osmotic minipump (Alzet®) for up to 3 days simultaneously with A II (900 μg/ kg/day) infused intraperitoneal by another osmotic minipump, the expected elevation of systolic blood pressure was inhibited a little. The antihypertensive effect of this peptide was sustained throughout the experimental period lasting for 3 days in rats on both sodium conditions. It was not accompanied by any changes in body weight, water intake, urine volume and urinary sodium excretion. Additional administration of ANP to rats made hypertensive for 3 days by infusion of A II reduced the blood pressure to a little extent but not to control levels, and the attenuating effect was sustained throughout the experimental period lasting for further 3 days on both sodium conditions. When the same dose of ANP was administered in combination with VP(7.2U/kg/day) for up to 3 days, the expected elevation of systolic blood pressure was completely inhibited. The antihypertensive effect of this peptide was sustained throughout the experimental period in rats on both sodium conditions. It was not accompanied by any changes in body weight, water intake, urine volume and urinary sodium excretions. These results indicate that subdepressor dose of ANP can modulate the hypertension induced by chronic infusion of AII and VP independent of sodium-water metabolism. Therefore it is suggested that ANP may be involved in the regulation of blood pressure via its attenuating effect to A II and VP.

Original languageEnglish
Pages (from-to)209-219
Number of pages11
JournalJapanese Journal of Nephrology
Volume29
Issue number2
DOIs
Publication statusPublished - 1987

Keywords

  • angiotensin II
  • atrial natriuretic polypeptide (ANP)
  • blood pressure
  • sodium-water excretion
  • vascular smooth muscle
  • vasopressin

ASJC Scopus subject areas

  • Nephrology

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