Table 1: Inhibitory effect of K+ channel blockers on the vasodilatation of tanshinone IIA in isolated SHR aortic rings contracted with phenylephrine or .

Contraction force (%)
Phenylephrine (10 nmol l−1)KCl (40 mmol l−1)
VehicleTanshinone IIA (10 μmol l−1)VehicleTanshinone IIA (10 μmol l−1)

Basal100## 100##
Glibenclamide (μmol l−1)
 1
 10
 100
Apamin (0.1 μmol l−1)
Charybdotoxin (0.1 μmol l−1)
Barium chloride (10 μmol l−1)
4-Aminopyridine (1 mmol l−1)

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. * and * versus basal level obtained from samples treated with the same volume of vehicle to dissolve testing K+ channel blockers in each group. # and ## versus value from sample received tanshinone IIA treatment in the absence of K+ channel blockers in each group.