Alterations in spontaneous contractions of rat ileum and jejunum after peritonitis

The aim of this study was to investigate the effects of peritonitis on spontaneous contractions of ileum and jejunum smooth muscles isolated from rats. Peritonitis was induced by cecal ligation and puncture in 8 rats. Another group of 8 rats underwent a sham operation and acted as controls. Twenty-four hours after the operation, the rats were killed, and their ileum and jejunum smooth muscles were excised and placed in circular muscle direction in a 10 ml organ bath. Changes in the amplitude and frequency of spontaneous contractions were analyzed before and after the addition of different antagonists. Peritonitis induced the decrease in the amplitude and frequency of spontaneous contractions in ileum and jejunum smooth muscles. In control groups, both ileum and jejunum, the amplitude and frequency of spontaneous contractions were significantly elevated in the presence of NG-nitro-l-arginine (l-NNA) and indomethacin. In peritonitis groups, both ileum and jejunum, the amplitude and frequency of spontaneous contractions were significantly enhanced in the presence of l-NNA, aminoguanidine, indomethacin and celecoxib compared to control values. In conclusion, peritonitis induces the decrease in the amplitude and frequency of spontaneous contractions of ileum and jejunum that can be attributed to the rise of nitric oxide synthase and cyclooxygenase isoforms levels.