Fig. 2.

organ culture with VEGF differentially alters contractile responses to myogenic stretch and potassium depolarization in an age-dependent manner. Endothelium-denuded carotid arteries from 28 fetal lambs and 23 adult sheep were prepared as matched sets of 3 adjacent segments from each animal. One member of each set was studied the day of euthansia (Fresh), one was studied after 48 h of organ culture under serum starvation conditions (Starved), and one was studied after 24 h of serum starvation followed by 24 h of culture with 3 ng/ml VEGF-A₁₆₅. Complete stress-strain relations were determined in all fetal (top panels) and adult (bottom panels) arteries. At each level of stress examined, the level of spontaneous, stretch-dependent tone was determined (right panels), as was the active response to depolarization with 120 mM potassium (left panels). As revealed by repeated measures ANOVA, organ culture with VEGF was without effect in fetal arteries but significantly increased maximum active stress and decreased maximum myogenic stress in adult arteries. Error bars indicate means ± SE.