Fig. 5.
Role of potassium channels in regulation of cerebrovascular myogenic tone in aged hypertensive mice. A–C: steady-state changes in diameter of MCAs isolated from young control, young + ANG II, aged control, and aged + ANG II mice in response to increases in intraluminal pressure in the absence and presence of iberiotoxin (Iberio) and 4-AP (which inhibit BKCa and voltage-activated K+ channels, respectively). Vascular diameters are expressed as percentage of the maximally dilated passive diameter of each vessel at 80 mmHg. Bar graphs show the effects of K+ channel blockers on myogenic tone (D) and pressure (160 mmHg)-induced increases in SMC [Ca2+]i in MCAs (E). Data are means ± SE (n = 8 in each group). *P < 0.05 vs. young control; #P < 0.05 vs. young + ANG II; &P < 0.05 vs. aged + ANG II.