Fig. 4. (  A ) The percent decrease in vessel diameter in response to phenylephrine before and after damaging the endothelium. (  B ) The percent recovery in vessel diameter in response to acetylcholine after vessel constriction precipitated by phenylephrine before and after damaging the endothelium. Vessels were perfused with serum (control) or serum plus Perftoran (PTN) or Pluronic F-127 (PF-127), with n = 12/group. #  P < 0.05 compared with both Perftoran and PF-127 exposure that preceded air perfusion. Values of ΔD^PE% and ΔD^ACH% are calculated from equations 1 and 2, respectively.