Changes in perfusion related to muscle length affect the pressor response to isometric muscle contraction

Masaki Mizuno, Ken Tokizawa, Isao Muraoka

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

To test the hypothesis that the dependence of the pressor response on muscle length is caused by changes in perfusion, we compared the cardiovascular responses to static contraction at short and long muscle lengths during free perfusion with those during circulatory arrest. Five males performed 2-min static knee extension exercise at 30% of maximal voluntary torque at each of two muscle lengths at a knee angle of 408 (short) and 908 (long). The subjects performed two trials - a free perfusion trial and a circulatory arrest trial. For circulatory arrest, an occlusion cuff placed around the proximal portion of the thigh was inflated to 250 mmHg 2 min before exercise. Mean arterial pressure (MAP), minute ventilation (VE), and the muscle oxygenation index in the vastus lateralis muscle were measured using near-infrared spectroscopy. In the free perfusion trial, MAP and VE were significantly greater during contractions at 908 than at 408 (p<0.05). The muscle oxygenation index was significantly lower during contractions at 908 than at 408 (p < 0.05). Circulatory arrest diminished these differences. These results suggest that the relationship between muscle length and the pressor response can be explained by changes in perfusion, which are related to muscle length.

Original languageEnglish
Title of host publicationOxygen Transport to Tissue XXXI
EditorsEiji Takahashi, Duane Bruley
Pages371-377
Number of pages7
DOIs
Publication statusPublished - 2010 Dec 1
Externally publishedYes

Publication series

NameAdvances in Experimental Medicine and Biology
Volume662
ISSN (Print)0065-2598

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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