Table 1 Values of ED₅₀, E_max and slope (S) of log dose–response curves of cromakalim in the presence and absence of antagonists, such as butylidenephthalide (Bdph), 4-aminopyridine (4-AP) and glibenclamide (GBC) in conscious normotensive rats

Change in systolic pressure (mmHg)

Bdph (30 mg/kg, i.p.)

−45 ± 5

−0.86 ± 0.04^a

8

Vehicle (1 ml/kg, i.p.)

−43 ± 6

−2.16 ± 0.29

8

4-AP (0.4 mg/kg, i.p.)

−30 ± 4

−0.82 ± 0.08^a

6

Vehicle (1 ml/kg, i.p.)

−34 ± 3

−1.83 ± 0.06

6

GBC (10 mg/kg, i.v.)

−53 ± 6

−1.08 ± 0.20

6

Vehicle (1 ml/kg, i.v.)

−47 ± 4

−0.72 ± 0.15

6