Effect of long-term tilt on mechanical and electrical properties of rat saphenous vein

E. Monos, S. J. Contney, A. W. Cowley, W. J. Stekiel

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Abstract

Femoral vein pressure in adult male Sprague-Dawley rats kept in specially designed tubelike cages rose immediately from a control value of 2.9 ± 0.2 (SE) mmHg to a gravity-induced sustained value of 5.9 ± 0.2 mmHg on initiation of a 2-wk 45° head-up tilt period. Femoral arterial pressure was not altered by tilting. In 2 wk mean external diameter, but not total wall thickness, of in vitro distal saphenous vein segments from tilted rats was increased ~ 30% above that of segments from nontilted controls at each of four successive 5-mmHg intraluminal pressure (IP) increments applied bewtween 0 and 20 mmHg. Consequently, in tilted rats isobaric stress was increased 38% at low and 24% at high IP, whereas incremental distensibility was decreased at mild IP. Vascular smooth muscle (VSM) in tilted rat vein, but not artery, was hyperpolarized relative to controls both in vitro at normal physiological pressures [membrane potential (E(m)) = -58.2 ± 0.8 vs. -52.4 ± 0.8 mV, respectively] and in situ during local neural blockade (E(m) = -61.3 ± 2.3 vs. -53.5 ± 0.5 mV, respectively). The conclusion is that a moderate chronic elevation of IP in a vein results in hyperpolarization of its VSM and an elevation of its total capacity due to an as yet unexplained mechanism of physiological adaptation.

Original languageEnglish
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume256
Issue number4
Publication statusPublished - 1989

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Saphenous Vein
Pressure
Vascular Smooth Muscle
Veins
Physiological Adaptation
Femoral Vein
Gravitation
Thigh
Membrane Potentials
Sprague Dawley Rats
Arterial Pressure
Arteries
Head

ASJC Scopus subject areas

  • Physiology

Cite this

Effect of long-term tilt on mechanical and electrical properties of rat saphenous vein. / Monos, E.; Contney, S. J.; Cowley, A. W.; Stekiel, W. J.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 256, No. 4, 1989.

Research output: Contribution to journalArticle

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AU - Contney, S. J.

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