Endothelium-dependent and -independent vasoactive actions of a Japanese kampo medicine, Saiko-ka-ryukotsu-borei-to.

Abstract

Saiko-ka-ryukotsu-borei-to (TJ-12) is a Japanese kampo medicine used clinically for the treatment of hypertension and atherosclerosis. We investigated the effects of TJ-12 on the contraction of rat thoracic aorta induced by norepinephrine, 5-hydroxytryptamine and high potassium. TJ-12 relaxed endothelium-denuded rings, which had been precontracted with 1 microM norepinephrine, in a dose-dependent manner with an IC50 of 50 micrograms/mL. However, in the presence of TJ-12, endothelium-intact rings initially showed enhanced norepinephrine-induced contraction, followed by relaxation. Interestingly, TJ-12 dose-dependently reversed nitric oxide (2 microM)-induced relaxation of norepinephrine-induced precontraction ofendothelium-denuded rings, with an IC50 of 20 micrograms/mL. In serotonin-contracted rings, TJ-12 caused slight, though statistically significant, relaxation only at high doses (> 200 micrograms/mL). In constrat to these receptor-mediated contractions, TJ-12 failed to affect the tension produced by high potassium 40 mM). These results suggest that the antihypertensive effects of TJ-12 could be related to inhibition of norepinephrine-induced vasoconstriction. In addition, our in vitro experiments revealed an inhibitory effect on nitric oxide-induced relaxation.

• Authors: M J Wei, F Shintani, S Kanba, G Yagi, M Asai, R Kato, T Nakaki
• Journal: Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie (Biomed Pharmacother) Vol. 51 Issue 1 Pg. 38-43 ( 1997) ISSN: 0753-3322 [Print] France
• PMID: 9084728 (Publication Type: Journal Article)

Chemical References

• Materia Medica
• Vasoconstrictor Agents
• Vasodilator Agents
• Nitric Oxide
• Serotonin
• Potassium
• Norepinephrine

Topics

• Analysis of Variance
• Animals
• Aorta, Thoracic (drug effects, physiology)
• Dose-Response Relationship, Drug
• Endothelium, Vascular (drug effects)
• Japan
• Male
• Materia Medica (administration & dosage, pharmacology)
• Muscle Contraction (drug effects)
• Muscle, Smooth (drug effects)
• Nitric Oxide (pharmacology)
• Norepinephrine (pharmacology)
• Potassium (pharmacology)
• Rats
• Serotonin (pharmacology)
• Vasoconstrictor Agents (pharmacology)
• Vasodilator Agents (pharmacology)