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KMID : 0363320000210030377
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Journal of Korean Oriental Internal Medicine
2000 Volume.21 No. 3 p.377 ~ p.388
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Effect of Sunghyangchungisan on Contractile Reactivity and metabolism in Isolated Rabbit Carotid Artery
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Kim Young-Kyun
Kwon Jung-Nam
Kim Jong-Hoon
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Abstract
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Objective : This study was undertaken to evaluate the effect of Sunghyangchungisan (SHCS) on the regulation of vascular tone and Cα²+ metabolism in arterial tissues. Vascular rings isolated from rabbit carotid artery were myographed isometrically in isolated organ baths and the effect of SHCS on contractile activities, endothelial function and Cα²+ metabolism were determined.
Methods : In phentobarbital sodium-anesthetized rabbits, SHCS administered through ear vein (100 mg/Kg body wt.) or intragastric dwelling tube (300 mg/Kg body wt.) attenuated phenylephrine (PE, 10 /Kg, i.v.)-induced increases in both systolic and diastolic cartoid arterial blood pressure.
Results : In experiments with isolated arterial strips, SHCS relaxed arterial rings which were pre-contracted by phenylephrine (PE, 1 μM ). The responses to SHCS were partially dose-dependent at concentrations lower than 0.5 mg/ml. When SHCS was applied prior to the exposure to PE, it inhibited the PE-induced contraction by a similar magnitude which was comparable to the relaxation of pre-contracted arterial rings. Washout of SHCS after observing its relaxant effect resulted in a full recovery of PE-induced contractions, indicating that the action mechanism is reversible. The observation that SHCS did not change the ED of PE oh its dose-response curve ruled out the possible interaction of SHCS with -receptors. The relaxant effect of SHCS was not affected by removal of endothelium or a nitric oxide synthase inhibitor, L-NAME. Methylene blue, an inhibitor of the soluble guanylate cyclase, did not affect the relaxant effect of SHCS. These results suggest that the action of SHCS is not mediated by the endothelium nor soluble guanylate cyclase. Constant cGMP production determined in arterial strips in the presence or absence of SHCS is consistent with this conclusion. When contraction was induced by additive application of Cα²+ in arterial rings which were pre-depolarized by high Κ+ in a Cα²+-free solution, the relaxant effect of SHCS was attenuated by increasing the Cα²+ concentration. SHCS, when applied to the arterial rings pre-contracted by PE and then relaxed by nifedipine, a Cα²+ channel blocker, did not show additive relaxation. SHCS partially blocked Cα²+ influx stimulated by PE and high Κ+ which was determined by 5-min 45Cα uptake, while it did not affect Cα²+ efflux.
Conclusions : From above results, it is suggested that SHCS relax PE-induced contraction of rabbit carotid artery in an endothelium independent manner, andinhibition of Cα²+ influx may contribute to the underling mechanism.
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KEYWORD
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Sunghyangjeongki-San, contractile reactivity, Ca²+metabolism, phenylephrine
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