Fig. 6. Detection of inducible nitric oxide synthase (iNOS) transcripts (298 base pairs [bp]) by reverse-transcription polymerase chain reaction in messenger RNA extracted from left ventricular tissue samples obtained from rabbits before (control;  lane 1 ), immediately after (trigger;  lane 3 ), or 24 h after (mediator;  lane 2 ) prolonged (2-h) administration of 1.0 minimum alveolar concentration isoflurane or from rabbits exposed to six cycles of brief (4-min) coronary artery occlusion and reperfusion (repetitive ischemia;  lane 4 ). 18S ribosomal RNA (rRNA; 489 bp) served as internal standard for each sample. Products were analyzed on a 2% agarose gel stained with SYBR gold (  top panel ). Histograms illustrating iNOS band density are depicted in the  bottom panel . Values are expressed relatively to the intensity of bands obtained from rabbits that were not exposed to isoflurane.