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Background and Objective: Biological activity of hydrogen sulphide in smooth muscle of vessel and non-vessel tissue are contradictory. The aim of this study was to examine the effect of hydrogen sulphide on smooth activity of muscle mice jejunum. Materials and Methods: Experiments were performed on mice jejunum and motor activity was recorded from in vitro segments of jejunum ~ 4 cm in length. jejunal segments were mounted horizontally in separate perfusion chamber. Furthermore, using vanilloid receptor 1 deficient mice (VR 1-/-) we tested hypothesis that extrinsic sensory nerves mediated alterations, in motor activity responses in the presence different concentration of of hydrogen sulphide (100-3000 μM). Results: Serosal application of NaHS (as hydrogen sulphide donor) produced a dose-dependent inhibition of motor activity that are not significantly different between VR 1-/- and VR 1 +/+ mice. In the presence of TTX (1μM) NaHS (300µM) caused a reduction in basal tone (19.5%, p<0.05, n=5) and inhibited the contraction evoked by 30µM bethanechol by 55% (n=5, p<0.05). Conclusion: This study showed that hydrogen sulphide is an important motor activity inhibitor in mice jejunum.

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Background and Objective: Hydroalcholic extract of Peppermint is traditionally used for gastrointestinal disorders. This study was done to evaluate the effect of Peppermint extract on the mice colon motor activity following immobilization stress.

Methods: In this experimental study, 30 male Albino mice were randomly allocated into the three groups; including control, stress and stress + Peppermint oil groups (n=10). The second group as a stress group exposed to immobilization stress for four hours during three days. Third group as stress plus Peppermint oil group was exposed to stress in addition to administration of 27 mg/kg/bw Peppermint oil intraperitoneally prior to stress. After three days, intestinal and peristaltic activity was recorded using pressure transducer from in vitro segments of colon (4-5 cm in length. Also, fecal weight, food intake and body weight was measured for each mouse for in vivo condition.

Results: The mean±SD of fecal weight after three times stress immobilization was 1.36±0.71, 1.06±0.6 and 0.47±0.39 gr in control, stress and Stress + Peppermint oil groups, respectively (P<0.05). The mean±SD of internal luminal pressure after three times stress immobilization was 4.47±1.15, 3.48±1.25 and 0.77±0.37 mm/hg in control, Stress and stress + Peppermint oil groups, respectively (P<0.05).

Conclusion: Peppermint oil is a strong inhibitor for colon motor activity following immobilization stress.