Figure 7. Contribution of K_ATP channels to vascular tone in mesenteric BPN and BPH arteries.

A, dose–response effect of pinacidil on the changes in diameter obtained in representative BPN and BPH mesenteric arteries. The arteries were pressurized to 70 mmHg in the presence of 0.5 μm phenylephrine to facilitate quantification of the pinacidil dilatory response. At the end of the experiments, the minimal and maximal arterial diameters were determined by sequential application of 10 μm phenylephrine (grey box) and a Ca²⁺-free solution (hatched box), respectively. B, summary of the effects of pinacidil at different concentrations in BPN (squares) and BPH (circles). Data are normalized to the maximal diameter values obtained in Ca²⁺-free solution and are expressed as a percentage of relaxation. Averaged data from five BPN and five BPH arteries were fitted to the sigmoidal functionobtaining an apparent EC₅₀ for pinacidil of 5.58 and 162.17 μm in BPN and BPH arteries, respectively.