Figure 6. Kir channels mediate vasodilatation in response to muscarinic receptor and TRPV4 channel agonists .

Arterial diameter measurements were performed in third‐order mesenteric arteries constricted by intravascular pressure (80 mmHg). Carbachol (CCh) and GSK101 were used to activate the muscarinic receptors and TRPV4 channels, respectively. A, representative diameter traces show vasodilatation in response to CCh and GSK101 in the presence or absence of Ba²⁺. Averaged data summarize the effect of Kir channel inhibition with Ba²⁺ on dilatations in response to CCh (B) and GSK101 (C; n = 6 arteries; *P < 0.05 using one‐way ANOVA). The data are means ± SEM. D, representative diameter trace (left) and averaged diameter data (right) for CCh‐ and GSK101‐induced dilatations in the presence or absence of the selective Kir2.x channel inhibitor ML‐133 (n = 4 arteries; *P < 0.001 using Student's t test). E, a representative diameter trace from an EC‐Kir2.1 ^−/− mouse showing the dilatations in response to CCh, GSK101 and NS309 in the mesenteric arteries (left) and averaged diameter data for CCh‐, GSK101‐ and NS309‐induced dilatations in the mesenteric arteries from EC‐Kir2.1 ^−/− mice (right; n = 4 arteries; *P < 0.05 using one‐way ANOVA).