Figure 3: Role of endothelium and K+ channels in PPARα agonist-mediated relaxations. The effects of nitric oxide synthase, cyclooxygenase, and endothelial denudation on the relaxant response of GW7647 (a) and WY14643 (c) in WT mice aortic rings ( 𝑛 = 3 –5). L-NAME or indomethacin or endothelial denudation had no effect on GW7647- and WY14643-mediated aortic relaxations. Responses to GW7647 (b) and WY14643 (d) after pretreatment of aortic rings with elevated external KCI (80 mM), 10−7 M Iberiotoxin (IbTX), 3 × 10−3 M 4-aminopyridine (4-AP), 10−5 M glibenclamide ( 𝑛 = 3 –6). Elevated KCI as well as glibenclamide resulted in attenuation of both GW7647- and WY14643-mediated relaxations. The other K+ channel inhibitors did not, however, alter the relaxations to PPARα agonists. Data are means ± SEM. *Indicates P ≤ 0.05.