Fig. 3. Acetylcholine-induced relaxation of aortic rings from Sham, Shock, and Resuscitated groups anesthetized with isoflurane ( A and C ) or isoflurane with adjunct nitrous oxide ( B and D ), and in the absence of indomethacine ( A and B ) or presence of indomethacine ( C and D ). Concentration-response curves of Sham groups ( closed circle ), Shock groups ( open circles ) and Resuscitated groups ( triangular up ) are expressed as percentage of preconstriction value to phenylephrine (0.1 mm) and are presented as mean ± SD. INDO = indomethacine; ISO = isoflurane; N2O = nitrous oxide.