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Vasorelaxation of rat thoracic aorta caused by 14-deoxyandrographolide.
- Source :
-
Clinical and experimental pharmacology & physiology [Clin Exp Pharmacol Physiol] 1998 Jun; Vol. 25 (6), pp. 424-9. - Publication Year :
- 1998
-
Abstract
- 1. The pharmacological effects of 14-deoxyandrographolide on rat isolated thoracic aorta were examined. 2. 14-Deoxyandrographolide (2.5-120 mumol/L) inhibited contractions induced by phenylephrine (PE; 0.1 mumol/L) and high K+ (80 mmol/L) in a concentration-dependent manner in endothelium-intact aorta. The effect was attenuated in endothelium-denuded aorta without modifying the maximal response. Like verapamil, 14-deoxyandrographolide produced a much greater vasorelaxant effect in aorta precontracted by KCl than by PE. 14-Deoxyandrographolide (20-60 mumol/L) also inhibited responses of the rat aorta to PE. 3. In Ca(2+)-free medium (KCl 55 mmol/L), 14-deoxyandrographolide (20-80 mumol/L) antagonized Ca(2+)-induced vasocontraction in a concentration-dependent manner and transient contractions induced by both caffeine (10 mmol/L) and nor-adrenaline (1 mumol/L) were suppressed or almost abolished by 14-deoxyandrographolide. 4. The vasorelaxant effect of 14-deoxyandrographolide was partially antagonized by NG-nitro-L-arginine methyl ester (25 mumol/L), a specific and competitive nitric oxide synthase (NOS) inhibitor, and methylene blue (10 mumol/L), a soluble guanylate cyclase inhibitor, but was not affected by indomethacin (20 mumol/L), a cyclo-oxygenase inhibitor, or glibenclamide (10 mumol/L), an ATP-sensitive K(+)-channel blocker. 5. These results suggest that the vasorelaxant activity of 14-deoxyandrographolide may be mediated via the activation of NOS and guanylate cyclase, as well as the blockade of Ca2+ influx through both voltage- and receptor-operated Ca2+ channels.
- Subjects :
- Animals
Caffeine pharmacology
Calcium physiology
Central Nervous System Stimulants pharmacology
Cyclooxygenase Inhibitors pharmacology
Enzyme Inhibitors pharmacology
Guanylate Cyclase antagonists & inhibitors
In Vitro Techniques
Male
Muscle Relaxation drug effects
Nitric Oxide Synthase antagonists & inhibitors
Norepinephrine pharmacology
Phenylephrine pharmacology
Rats
Rats, Sprague-Dawley
Vasoconstrictor Agents pharmacology
Aorta, Thoracic drug effects
Diterpenes pharmacology
Muscle, Smooth, Vascular drug effects
Vasodilator Agents pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 0305-1870
- Volume :
- 25
- Issue :
- 6
- Database :
- MEDLINE
- Journal :
- Clinical and experimental pharmacology & physiology
- Publication Type :
- Academic Journal
- Accession number :
- 9673817
- Full Text :
- https://doi.org/10.1111/j.1440-1681.1998.tb02226.x