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Comparative effects of the alpha-adrenoceptor agonists noradrenaline, phenylephrine and clonidine in the human saphenous vein in vivo and in vitro

Sjöberg, Trygve LU ; Norgren, Lars LU ; Andersson, K E and Steen, Stig LU (1989) In Acta Physiologica Scandinavica 136(3). p.463-471
Abstract
The alpha-adrenoceptor-mediated contractile effects of noradrenaline (alpha 1 + alpha 2), phenylephrine (alpha 1) and clonidine (alpha 2) on human saphenous veins were investigated in vivo and in vitro. By infusion (0.3 ml min-1) of the drugs (increasing concentrations in the infused solution) into distended (40 mmHg) saphenous veins in six healthy subjects, local vasoconstriction was induced, measured by a photo-electric device. The drugs induced dose-dependent contractions in all subjects, and dose-response curves were constructed. These were compared with concentration-response curves based on in-vitro results. Macroscopically normal saphenous veins, taken at saphenousectomies, were used, and the preparations were contracted... (More)
The alpha-adrenoceptor-mediated contractile effects of noradrenaline (alpha 1 + alpha 2), phenylephrine (alpha 1) and clonidine (alpha 2) on human saphenous veins were investigated in vivo and in vitro. By infusion (0.3 ml min-1) of the drugs (increasing concentrations in the infused solution) into distended (40 mmHg) saphenous veins in six healthy subjects, local vasoconstriction was induced, measured by a photo-electric device. The drugs induced dose-dependent contractions in all subjects, and dose-response curves were constructed. These were compared with concentration-response curves based on in-vitro results. Macroscopically normal saphenous veins, taken at saphenousectomies, were used, and the preparations were contracted isometrically in organ baths by the agonists. From the curves obtained in vivo and in vitro, the relative potencies of phenylephrine and clonidine (in relation to noradrenaline) were calculated and compared. The relative potencies of phenylephrine in vivo (76%) and in vitro (82%) did not differ significantly. However, the relative potency of clonidine was significantly (P less than 0.05) lower in vivo (90%) than in vitro (99%). Thus, it is concluded that there are differences between the results obtained in vivo and in vitro, stressing the importance of comparative in vivo-in vitro studies. (Less)
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Contribution to journal
publication status
published
subject
in
Acta Physiologica Scandinavica
volume
136
issue
3
pages
463 - 471
publisher
Wiley-Blackwell
external identifiers
  • pmid:2568732
ISSN
0001-6772
language
English
LU publication?
yes
id
077ff602-c9de-46b0-9190-60f36dab89eb (old id 1104841)
date added to LUP
2008-08-06 16:00:26
date last changed
2016-04-16 05:21:08
@article{077ff602-c9de-46b0-9190-60f36dab89eb,
  abstract     = {The alpha-adrenoceptor-mediated contractile effects of noradrenaline (alpha 1 + alpha 2), phenylephrine (alpha 1) and clonidine (alpha 2) on human saphenous veins were investigated in vivo and in vitro. By infusion (0.3 ml min-1) of the drugs (increasing concentrations in the infused solution) into distended (40 mmHg) saphenous veins in six healthy subjects, local vasoconstriction was induced, measured by a photo-electric device. The drugs induced dose-dependent contractions in all subjects, and dose-response curves were constructed. These were compared with concentration-response curves based on in-vitro results. Macroscopically normal saphenous veins, taken at saphenousectomies, were used, and the preparations were contracted isometrically in organ baths by the agonists. From the curves obtained in vivo and in vitro, the relative potencies of phenylephrine and clonidine (in relation to noradrenaline) were calculated and compared. The relative potencies of phenylephrine in vivo (76%) and in vitro (82%) did not differ significantly. However, the relative potency of clonidine was significantly (P less than 0.05) lower in vivo (90%) than in vitro (99%). Thus, it is concluded that there are differences between the results obtained in vivo and in vitro, stressing the importance of comparative in vivo-in vitro studies.},
  author       = {Sjöberg, Trygve and Norgren, Lars and Andersson, K E and Steen, Stig},
  issn         = {0001-6772},
  language     = {eng},
  number       = {3},
  pages        = {463--471},
  publisher    = {Wiley-Blackwell},
  series       = {Acta Physiologica Scandinavica},
  title        = {Comparative effects of the alpha-adrenoceptor agonists noradrenaline, phenylephrine and clonidine in the human saphenous vein in vivo and in vitro},
  volume       = {136},
  year         = {1989},
}