Table 2.

Effect of K⁺ channel blockers on the inhibition of tanshinone IIA-induced changes in [Ca²⁺]_i in A7r5 cells^a.

	[Ca2+]i (nmol l−1)
	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	440.2 ± 29.3##	256.4 ± 32.5**	423.7 ± 32.4##	246.5 ± 27.6**
Glibenclamide (μmol l−1)
1	451.3 ± 35.7##	292.1 ± 27.6**	429.7 ± 37.2##	283.5 ± 29.8**
10	458.7 ± 30.2##	371.6 ± 23.7∗,##	432.6 ± 33.2##	386.2 ± 31.5∗,##
100	462.6 ± 32.3##	405.3 ± 31.4##	440.5 ± 34.6##	418.6 ± 28.6##
Apamin (0.1 μmol l−1)	459.5 ± 39.2##	264.8 ± 28.4**	439.8 ± 29.7##	254.3 ± 27.2**
Charybdotoxin (0.1 μmol l−1)	460.3 ± 34.2##	257.2 ± 26.7**	441.2 ± 31.4##	252.9 ± 30.6**
Barium chloride (10 μmol l−1)	456.7 ± 33.9##	270.7 ± 32.4**	436.5 ± 28.6##	261.7 ± 25.9**
4-Aminopyridine (1 mmol l−1)	462.5 ± 30.1##	262.3 ± 34.1**	443.8 ± 32.5##	258.3 ± 28.6**

^aData (mean ± SD) were obtained from six experiments. The [Ca²⁺]_i obtained from A7r5 cells without any treatment was 214.7 ± 34.2 nmol l⁻¹. Data from phenylephrine (10 nmol l⁻¹)- or KCl (40 mmol l⁻¹)-treated cells without K⁺ channel blockers treatment were served as basal level in each group. *P < .05 and **P < .01 versus basal level obtained from cells treated with the same volume of vehicle to dissolve testing K⁺ channel blockers in each group. ^# P < .05 and ^## P < .01 versus value from cells received tanshinone IIA treatment in the absence of K⁺ channel blockers in each group.