Article date: October 1993
By: JAYE P. F. CHIN, ROBYN M. HURLSTON, ANTHONY M. DART, in Volume 36, Issue 4, pages 303-307
The functional role of endogenous cyclo‐oxygenase products was examined in the human forearm isolated vein.
Six healthy normal adult males (age > 18 years old) were recruited. Forearm veins were biopsied and ring segments mounted in standard organ baths for recording of isometric force.
Noradrenaline (‐log molar EC50: 7.75 ± 0.19; –log molar threshold concentration: 8.80 ± 0.20), 5‐hydroxytryptamine (–log molar EC50: 7.52 ± 0.17; –log molar threshold concentration: 9.50 ± 0.64), angiotensin II (–log molar threshold concentration: 9.00 ± 0.28) and endothelin‐1 (–log molar threshold concentration: 9.13 ± 0.47) were equipotent in this preparation. Indomethacin (10 μ) had no effect on either the threshold concentration or EC50 of noradrenaline, 5‐hydroxytryptamine nor the threshold concentration of angiotensin II nor endothelin‐1.
Sodium nitroprusside (1 N‐10 μ) relaxed noradrenaline‐precontracted preparations. Evidence of minimal endothelial influence was confirmed by the lack of relaxant response to acetylcholine (1 N‐10 μ). Histology using silver staining confirmed that endothelial cells were absent over greater than 90% of the lumen surface.
We conclude that endogenous prostanoids derived from smooth muscle cells, either released basally or agonist‐stimulated, do not play a role in the regulation of vascular tone in the human forearm isolated vein.
The functional role of endogenous cyclo‐oxygenase products was examined in the human forearm isolated vein.
Six healthy normal adult males (age > 18 years old) were recruited. Forearm veins were biopsied and ring segments mounted in standard organ baths for recording of isometric force.
Noradrenaline (‐log molar EC50: 7.75 ± 0.19; –log molar threshold concentration: 8.80 ± 0.20), 5‐hydroxytryptamine (–log molar EC50: 7.52 ± 0.17; –log molar threshold concentration: 9.50 ± 0.64), angiotensin II (–log molar threshold concentration: 9.00 ± 0.28) and endothelin‐1 (–log molar threshold concentration: 9.13 ± 0.47) were equipotent in this preparation. Indomethacin (10 μ) had no effect on either the threshold concentration or EC50 of noradrenaline, 5‐hydroxytryptamine nor the threshold concentration of angiotensin II nor endothelin‐1.
Sodium nitroprusside (1 N‐10 μ) relaxed noradrenaline‐precontracted preparations. Evidence of minimal endothelial influence was confirmed by the lack of relaxant response to acetylcholine (1 N‐10 μ). Histology using silver staining confirmed that endothelial cells were absent over greater than 90% of the lumen surface.
We conclude that endogenous prostanoids derived from smooth muscle cells, either released basally or agonist‐stimulated, do not play a role in the regulation of vascular tone in the human forearm isolated vein.
DOI: 10.1111/j.1365-2125.1993.tb00368.x
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