Pressure dependence of baroreceptor-mediated vasoconstriction in rat skeletal muscle

J. M. Lash, A. A. Shoukas

Research output: Contribution to journalArticlepeer-review

Abstract

To determine whether microvessels in resting or contracting skeletal muscle constrict during baroreceptor activation, vascular diameters were measured in the spinotrapezius muscle of adult rats (n = 12) during occlusion of the common carotid arteries. Neural and myogenic components were distinguished using two types of occlusion: 1) 'normal' (arterial pressure was allowed to increase with baroreceptor activation) and 2) 'isobaric' (arterial pressure was maintained constant by decreasing blood volume). During normal occlusions, intermediate and small arteriolar diameters decreased in resting and contracting muscle (10-15% and 25-30%, respectively). Large arterioles and all-sized venules distended slightly (~5%) in resting muscle, but diameters were maintained or decreased in contracting muscle. When arterial pressure was maintained constant (isobaric), the microvascular responses to baroreceptor activation in both resting and contracting muscle were essentially eliminated. We conclude that nearly all the arteriolar constriction observed in the spinotrapezius muscle during normal carotid artery occlusion is myogenic in origin, secondary to increased arterial pressure. This pressure-dependent constriction is augmented during skeletal muscle contraction and functional vasodilation.

Original languageEnglish (US)
Pages (from-to)2551-2558
Number of pages8
JournalJournal of applied physiology
Volume70
Issue number6
DOIs
StatePublished - 1991
Externally publishedYes

Keywords

  • arterioles
  • carotid occlusion
  • functional vasodilation
  • myogenic
  • skeletal muscle contraction
  • spinotrapezius
  • venules

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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