Figure 6.
Inhibition of β3-adrenergic induced relaxation in rat aorta by potassium channel blockers. The mean curves resulting from subtraction of the spontaneous relaxation of control vessel pre-treated or not with potassium channels blockers are shown. (A) Concentration-response curves for SR 58611A in the absence (n=9) and presence of 0.1 μM iberiotoxin (n=8) in rat thoracic aortic rings constricted with phenylephrine. (B) Concentration response curves for SR 58611A in the absence (n=21) and presence of 1 μM glibenclamide (n=6) or 100 μM tolbutamide (n=6) in rat thoracic aortic rings constricted with phenylephrine. (C) Concentration response curves for SR 58611A in the absence (n=21) and presence of 1 mM 4-aminopyridine (n=7) in rat thoracic aortic rings constricted with phenylephrine. Results are expressed as the percentage of relaxation from the steady-state contraction level induced by phenylephrine. Each point is the mean of n experiments, and the vertical lines show the s.e. of the mean. When no error bar is shown, the error is smaller than the symbol. *P<0.05 and **P<0.01 indicate significant differences from control.