Figure 2. Percentage relaxation versus logarithm of concentration of (A) isoproterenol and (B) nitroprusside. Epithelial rubbing attenuated dilatory response to the epithelium-dependent agonist isoproterenol (P <0.01) but not to the epithelium-independent agonist nitroprusside (P = 0.37). *P < 0.05 versus epithelium-intact control.