Fig. 1
Experimental design. The transmural pressure of the superior mesenteric artery and uterine artery was adjusted to balance under a basal tension of 3 mN for 1 h. After zero adjustment, 60 mM potassium chloride (KCl) was used twice to stimulate vasoconstriction for 10 min. The integrity of vascular endothelial function was tested (phenylephrine, PE, 10− 9 to 10− 4 M; acetylcholine, ACH, 10− 9 to 10− 4 M). Gradually increasing concentrations of vasopressors (phenylephrine, norepinephrine, vasopressin, metaraminol) were added to the water bath (10− 9–10− 5/10− 4 M). Each drug concentration acted for 2 min