Vasoconstriction during venous congestion: Effects of venoarteriolar response, myogenic reflexes, and hemodyoamics of changing perfusion pressure

Kazunobu Okazaki, Qi Fu, Emily R. Martini, Robin Shook, Colin Conner, Rong Zhang, Craig G Crandall, Benjamin D Levine

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

We dissected the relative contribution of arteriovenous hemodynamics, the venoarteriolar response (VAR), and the myogenic reflex toward a decrease in local blood flow induced by venous congestion. Skin blood flow (SkBF) was measured in 12 supine subjects via laser-Doppler flowmetry 1) over areas of forearm and calf skin, in which the VAR was blocked by using eutectic mixture of local anesthetics (EMLA sites) and 2) over the contralateral forearm or calf skin (control sites), using two different techniques: limb dependency of 23-37 cm below the heart and cuff inflation to 40 mmHg. During limb dependency, SkBF decreased at the control sites, whereas it remained unchanged at the EMLA sites. In contrast, during cuff inflation, SkBF decreased at the control sites and also decreased at the EMLA sites. The percent change in SkBF from baseline was greater during cuff inflation than limb dependency at both the control sites and the EMLA sites. Estimated skin vascular resistance remained unchanged at the EMLA sites during cuff inflation, as well as limb dependency. Thus the decrease in SkBF during venous congestion with cuff inflation is not solely due to the cutaneous VAR but also to a reduction in local perfusion pressure. The VAR is therefore most specifically quantified by venous congestion induced by limb dependency, rather than cuff inflation. Finally, from both techniques, we calculated that during venous congestion induced by limb dependency (calf), ∼45% of the nonbaroreflex vasoconstriction is induced by the VAR and ∼55% by the myogenic reflex.

Original languageEnglish (US)
Pages (from-to)R1354-R1359
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume289
Issue number5 58-5
DOIs
StatePublished - Nov 2005

Keywords

  • Axon reflex
  • Local circulatory control

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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