Active and passive arteriolar regulation in spontaneously hypertensive rats

H. Bohlen, Julia M. Lash

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

This study determined to what extent active and passive wall tensions increase in in vivo intestinal arterioles of 13- to 15-week-old and 25- to 27-week-old spontaneously hypertensive rats (SHR) to maintain normal or smaller arteriolar diameters during microvascular hypertension. Acetylcholine and nitroprusside were used to determine whether vascular muscle relaxation to endothelium-derived relaxing factor or cyclic GMP is impaired. Large arterioles of hypertensive rats have passive tension-circumference relations that are steeper and shifted to the left compared with those of age-matched controls; passive resistance to distension limits vasodilation in hypertensive rats except at their naturally elevated arteriolar pressure. Passive tension contributes approximately 30% of the total resting tension in arterioles of hypertensive and normotensive rats because a greater passive tension occurs at the 20% to 25% constricted resting diameter in hypertensive rats. Absolute and relative changes in the diameter of SHR arterioles during acetylcholine and nitroprusside application were equal to or greater than those in Wistar-Kyoto rats. However, reduction in active tension was suppressed in older SHR and remained approximately 50% higher than that found in older Wistar-Kyoto rats during drug application. Vasoconstriction and increased passive resistance to distension of the arteriolar wall diminish the active tension required to maintain normal or smaller resting diameters against microvascular hypertension. However, the elevated microvascular pressure in hypertensive rats is required to allow near-normal dilation to compensate for their increased passive resistance to stretch and decreased ability to relax active tension through cyclic GMP mechanisms.

Original languageEnglish
Pages (from-to)757-764
Number of pages8
JournalHypertension
Volume23
Issue number6 I
StatePublished - Jun 1994

Fingerprint

Inbred SHR Rats
Arterioles
Inbred WKY Rats
Cyclic GMP
Nitroprusside
Acetylcholine
Hypertension
Pressure
Endothelium-Dependent Relaxing Factors
Muscle Relaxation
Vasoconstriction
Vasodilation
Blood Vessels
Dilatation
Pharmaceutical Preparations

Keywords

  • arterioles
  • endothelium-derived factors
  • hypertension

ASJC Scopus subject areas

  • Internal Medicine

Cite this

Active and passive arteriolar regulation in spontaneously hypertensive rats. / Bohlen, H.; Lash, Julia M.

In: Hypertension, Vol. 23, No. 6 I, 06.1994, p. 757-764.

Research output: Contribution to journalArticle

Bohlen, H. ; Lash, Julia M. / Active and passive arteriolar regulation in spontaneously hypertensive rats. In: Hypertension. 1994 ; Vol. 23, No. 6 I. pp. 757-764.
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