Inhibition of prostaglandin synthesis does not affect contractile responses to noradrenaline, serotonin, angiotensin II nor endothelin-1 in human forearm isolated veins.
1. The functional role of endogenous cyclo-oxygenase products was examined in the human forearm isolated vein. 2. 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. 3. 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 microM) had no effect on either the threshold concentration or EC50 of noradrenaline, 5-hydroxytryptamine nor the threshold concentration of angiotensin II nor endothelin-1. 4. Sodium nitroprusside (1 nM-10 microM) relaxed noradrenaline-precontracted preparations. Evidence of minimal endothelial influence was confirmed by the lack of relaxant response to acetylcholine (1 nM-10 microM). Histology using silver staining confirmed that endothelial cells were absent over greater than 90% of the lumen surface. 5. 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.
Chin
J P
JP
Alfred and Baker Medical Unit, Baker Medical Research Institute, Commercial Road, Prahran, Victoria 3181, Australia.
Hurlston
R M
RM
Dart
A M
AM
D000328:Adult; D000368:Aged; D000804:Angiotensin II / Q000494:pharmacology*; D019332:Endothelin-1 / Q000494:pharmacology; D005542:Forearm / Q000098:blood supply; D006801:Humans; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009638:Norepinephrine / Q000494:pharmacology; D011448:Prostaglandin Antagonists / Q000494:pharmacology*; D011453:Prostaglandins / Q000096:biosynthesis*; D012701:Serotonin / Q000494:pharmacology; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014680:Veins
D019332:Endothelin-1; D011448:Prostaglandin Antagonists; D011453:Prostaglandins; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D012701:Serotonin; D009638:Norepinephrine