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Effects of Ca2+ on ...
Effects of Ca2+ on force-velocity characteristics of normal and hypertrophic smooth muscle of the rat portal vein
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- Arner, Anders (author)
- Lund University,Lunds universitet,Kärlfysiologi,Forskargrupper vid Lunds universitet,Vascular Physiology,Lund University Research Groups
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- Malmqvist, Ulf (author)
- Lund University,Lunds universitet,Avdelningen för klinisk kemi och farmakologi,Institutionen för laboratoriemedicin,Medicinska fakulteten,Division of Clinical Chemistry and Pharmacology,Department of Laboratory Medicine,Faculty of Medicine
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- Uvelius, Bengt (author)
- Lund University,Lunds universitet,Urologi,Forskargrupper vid Lunds universitet,Urology,Lund University Research Groups
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(creator_code:org_t)
- 1985
- 1985
- English.
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In: Acta Physiologica Scandinavica. - 0001-6772. ; 124:4, s. 525-533
- Related links:
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Abstract
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- Portal hypertension was induced in rats by partial ligation of the hepatic branches of the portal vein. After 5 days of hypertension the portal veins were taken out and mounted for isometric and quick-release experiments. Portal veins from sham-operated normal rats served as controls. The ligated veins had an increased cross-sectional area, indicating smooth-muscle hypertrophy. Although the absolute magnitude of active force of these veins was increased, the active force per cross-sectional area was decreased, indicating an alteration in the properties of the contractile system. No difference in the Ca2+ concentration-response relations to K+-activated intact control and hypertrophic veins was found. In chemically skinned preparations, devoid of functional plasma membranes, the hypertrophic veins had similar Ca2+ sensitivity (in the presence of I microM calmodulin) but a lower force per cross-sectional area. Force-velocity relations were determined in K+-activated intact preparations. In control veins a reduction in extracellular Ca2+ was associated with a significant reduction in both isometric force and maximal shortening velocity (Vmax). In hypertrophic veins the decreased isometric force at maximal activation was associated with a low Vmax. A comparison between hypertrophic and submaximally stimulated control vessels showed corresponding Vmax and isometric force values. We conclude that the low isometric force of hypertrophic veins is associated with a lower rate of cross-bridge turnover. This could be an effect of alterations in the activation mechanisms or in the intrinsic properties of the contractile system itself.
Subject headings
- MEDICIN OCH HÄLSOVETENSKAP -- Klinisk medicin -- Urologi och njurmedicin (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Clinical Medicine -- Urology and Nephrology (hsv//eng)
- MEDICIN OCH HÄLSOVETENSKAP -- Medicinska och farmaceutiska grundvetenskaper -- Fysiologi (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Basic Medicine -- Physiology (hsv//eng)
- MEDICIN OCH HÄLSOVETENSKAP -- Medicinska och farmaceutiska grundvetenskaper -- Farmakologi och toxikologi (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Basic Medicine -- Pharmacology and Toxicology (hsv//eng)
- MEDICIN OCH HÄLSOVETENSKAP -- Medicinska och farmaceutiska grundvetenskaper -- Läkemedelskemi (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Basic Medicine -- Medicinal Chemistry (hsv//eng)
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- art (subject category)
- ref (subject category)
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