Fig. 3. Representative photomicrographs of immunofluorescent staining for endothelial nitric oxide synthase (eNOS; top panel ) and histograms illustrating eNOS expression ( bottom panel ) in left ventricular tissue samples obtained from rabbits before (control), immediately after (trigger), or 24 h after (mediator) prolonged (2 h) administration of 1.0 minimum alveolar concentration isoflurane in the absence (−) and presence (+) of N -nitro-l-arginine methyl ester (l-NAME). * Significantly ( P < 0.05) different from control. † Significantly ( P < 0.05) different from (−) l-NAME.