Antihypertension Induced by Tanshinone IIA Isolated from the Roots of Salvia miltiorrhiza

Table 1

Inhibitory effect of K⁺ channel blockers on the vasodilatation of tanshinone IIA in isolated SHR aortic rings contracted with phenylephrine or KCL^a.

	Contraction force (%)
	Phenylephrine (10 nmol l^−1)		KCl (40 mmol l^−1)
	Vehicle	Tanshinone IIA (10 μmol l^−1)	Vehicle	Tanshinone IIA (10 μmol l^−1)
Basal	100^##	24.9±5.1^∗∗	100^##	28.3±4.8^∗∗
Glibenclamide (μmol l^−1)
1	99.2±4.9^##	59.3±7.1^∗∗	98.6±5.8^##	53.5±4.9^∗∗
10	98.8±6.1^##	73.3±5.9^∗,#	98.2±4.9^##	78.6±6.4^∗,#
100	98.6±5.6^##	87.4±6.7^##	97.9±6.3^##	90.3±5.6^##
Apamin (0.1 μmol l^−1)	99.2±3.7^##	27.6±4.7^∗∗	98.4±4.7^##	29.5±5.7^∗∗
Charybdotoxin (0.1 μmol l^−1)	98.7±4.1^##	26.4±5.1^∗∗	98.6±5.3^##	31.2±4.9^∗∗
Barium chloride (10 μmol l^−1)	99.1±5.6^##	28.2±3.9^∗∗	97.8±4.6^##	30.5±5.1^∗∗
4-Aminopyridine (1 mmol l^−1)	98.6±3.9^##	27.9±4.2^∗∗	98.5±6.9^##	32.5±6.1^∗∗

^aThe preparation of isolated aortic rings from male SHR was described in Section 2. Data (mean ± SD) indicate the percentage dilations of the maximal contractions in eight experiments. Data from phenylephrine (10 nmol l⁻¹)- or KCl (40 mmol l⁻¹)-treated sample without K⁺ channel blockers treatment was served as basal level in each group. *𝑃<.05 and *𝑃<.01 versus basal level obtained from samples treated with the same volume of vehicle to dissolve testing K⁺ channel blockers in each group. ^#𝑃<.05 and ^##𝑃<.01 versus value from sample received tanshinone IIA treatment in the absence of K⁺ channel blockers in each group.