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In vivo effects of prostacyclin on segmental vascular resistances, on myogenic reactivity, and on capillary fluid exchange in cat skeletal muscle

Jahr, John LU ; Ekelund, Ulf LU and Grände, Per-Olof LU (1995) In Critical Care Medicine 23(3). p.523-531
Abstract
OBJECTIVE: To analyze the local circulatory effects of prostacyclin in skeletal muscle. DESIGN: A prospective experimental study. SETTING: A university laboratory. SUBJECTS: Twelve adult cats. INTERVENTIONS: The study was performed on autoperfused, sympathectomized gastrocnemius muscle. MEASUREMENTS AND MAIN RESULTS: Arterial blood flow, total and segmental vascular resistances (arterial vessels of > 25 microns, arterioles of < 25 microns, and veins), hydrostatic capillary pressure, tissue volume, myogenic reactivity, and the capillary filtration coefficient were followed. The capillary filtration coefficient reflects the functional capillary fluid exchange area. Myogenic reactivity was evaluated as the arteriolar resistance increase... (More)
OBJECTIVE: To analyze the local circulatory effects of prostacyclin in skeletal muscle. DESIGN: A prospective experimental study. SETTING: A university laboratory. SUBJECTS: Twelve adult cats. INTERVENTIONS: The study was performed on autoperfused, sympathectomized gastrocnemius muscle. MEASUREMENTS AND MAIN RESULTS: Arterial blood flow, total and segmental vascular resistances (arterial vessels of > 25 microns, arterioles of < 25 microns, and veins), hydrostatic capillary pressure, tissue volume, myogenic reactivity, and the capillary filtration coefficient were followed. The capillary filtration coefficient reflects the functional capillary fluid exchange area. Myogenic reactivity was evaluated as the arteriolar resistance increase after a standardized decrease in extravascular pressure. Arterial infusion of prostacyclin decreased vascular resistance by approximately 50% at the highest dose given (500 ng/kg/min). This effect was more pronounced on the arterial side, especially in arterial vessels of > 25 microns. Hydrostatic capillary pressure increased by 1.9 +/- 0.3 mm Hg, causing fluid filtration. The relative fluid filtration was less than that value shown for some other vasodilator drugs (isoprenaline, calcium-channel blockers, thiopental) in this muscle preparation. Capillary filtration coefficient decreased by 25%. Myogenic reactivity was depressed but to a lesser extent than previously observed for other vasodilator mechanisms (muscle exercise, beta-adrenergic receptor stimulation, thiopental infusion, nifedipine infusion). CONCLUSIONS: Prostacyclin is a vasodilator, both on the arterial and venous side, that restricts the increase in hydrostatic capillary pressure. The decrease in capillary filtration coefficient most likely reflects a decrease in capillary permeability, explaining the smaller relative filtration rate. The relatively well-preserved myogenic reactivity may imply a better preserved microvascular flow distribution and peripheral oxygen uptake. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Critical Care Medicine
volume
23
issue
3
pages
523 - 531
publisher
Lippincott Williams & Wilkins
external identifiers
  • pmid:7874905
  • scopus:0028953799
ISSN
1530-0293
language
English
LU publication?
yes
id
cbb7f7de-e1ea-49ce-9e7f-d23ddc0be8d1 (old id 1109051)
date added to LUP
2008-07-25 12:48:39
date last changed
2017-01-01 07:09:26
@article{cbb7f7de-e1ea-49ce-9e7f-d23ddc0be8d1,
  abstract     = {OBJECTIVE: To analyze the local circulatory effects of prostacyclin in skeletal muscle. DESIGN: A prospective experimental study. SETTING: A university laboratory. SUBJECTS: Twelve adult cats. INTERVENTIONS: The study was performed on autoperfused, sympathectomized gastrocnemius muscle. MEASUREMENTS AND MAIN RESULTS: Arterial blood flow, total and segmental vascular resistances (arterial vessels of &gt; 25 microns, arterioles of &lt; 25 microns, and veins), hydrostatic capillary pressure, tissue volume, myogenic reactivity, and the capillary filtration coefficient were followed. The capillary filtration coefficient reflects the functional capillary fluid exchange area. Myogenic reactivity was evaluated as the arteriolar resistance increase after a standardized decrease in extravascular pressure. Arterial infusion of prostacyclin decreased vascular resistance by approximately 50% at the highest dose given (500 ng/kg/min). This effect was more pronounced on the arterial side, especially in arterial vessels of &gt; 25 microns. Hydrostatic capillary pressure increased by 1.9 +/- 0.3 mm Hg, causing fluid filtration. The relative fluid filtration was less than that value shown for some other vasodilator drugs (isoprenaline, calcium-channel blockers, thiopental) in this muscle preparation. Capillary filtration coefficient decreased by 25%. Myogenic reactivity was depressed but to a lesser extent than previously observed for other vasodilator mechanisms (muscle exercise, beta-adrenergic receptor stimulation, thiopental infusion, nifedipine infusion). CONCLUSIONS: Prostacyclin is a vasodilator, both on the arterial and venous side, that restricts the increase in hydrostatic capillary pressure. The decrease in capillary filtration coefficient most likely reflects a decrease in capillary permeability, explaining the smaller relative filtration rate. The relatively well-preserved myogenic reactivity may imply a better preserved microvascular flow distribution and peripheral oxygen uptake.},
  author       = {Jahr, John and Ekelund, Ulf and Grände, Per-Olof},
  issn         = {1530-0293},
  language     = {eng},
  number       = {3},
  pages        = {523--531},
  publisher    = {Lippincott Williams & Wilkins},
  series       = {Critical Care Medicine},
  title        = {In vivo effects of prostacyclin on segmental vascular resistances, on myogenic reactivity, and on capillary fluid exchange in cat skeletal muscle},
  volume       = {23},
  year         = {1995},
}