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

M. J. Wei, F. Shintani, S. Kanba, G. Yagi, M. Asai, R. Kato, T. Nakaki

Research output: Contribution to journalArticle

4 Citations (Scopus)

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 μM norepinephrine, in a dose-dependent manner with an IC50 of 50 μg/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 μM)-induced relaxation of norepinephrine-induced precontraction of endothelium-denuded rings, with an IC50 of 20 μg/mL. In serotonin-contracted rings, TJ-12 caused slight, though statistically significant, relaxation only at high doses (>200 μg/mL). In contrast 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.

Original languageEnglish
Pages (from-to)38-43
Number of pages6
JournalBiomedicine and Pharmacotherapy
Volume51
Issue number1
DOIs
Publication statusPublished - Jan 1 1997

All Science Journal Classification (ASJC) codes

  • Pharmacology

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