Figure 3. (A) Percentage relaxation of the U46619-preconstricted vessel in response to changes in pressure gradients (Delta P) across the vessel when the perfusate was Krebs solution or heparinized Krebs solution. With heparinization, the Delta P-produced, flow-induced dilation was enhanced (P < 0.01). *P < 0.05 versus Krebs solution as the perfusate. (B) Percentage relaxation of the U46619-preconstricted vessel in response to changes in pressure gradients (Delta P) across the vessel with different perfusates. Flow-induced dilation was attenuated as the hemoglobin concentration of the perfusate was increased (P < 0.001). *P < 0.05 versus heparinized Krebs solution as the perfusate. +P < 0.05 versus diluted heparinized blood as the perfusate.