| Effect of motilin on the contractility of gastric smooth muscle via NO pathway in guinea pig (2009) | |||||||||
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| This study investigates the gastroprokinetic effects of motilin and erythromycin A (EM-A) and its potential mechanism in guinea pigs Cavia porcellus in vitro. Guinea pig stomach strips were mounted under organ baths containing Krebs solution. Motilin, EM-A, Nω- Nitro-L-arginine (L-NNA), L-arginine (L-AA) were added to the bathing solution in a non-cumulative way. Then the effects of motilin and EM-A was studied during electrical field stimulation (EFS) in the absence and presence of L-NNA and L-AA in the gastric anturm and fundus of guinea pigs. In addition, we observed the co-expression of motilin receptors and neuronal nitric oxide synthase (nNOS) in the gastric myenteric plexus of guinea pigs by fluo-immunohistochemistry. The results showed that the Circular muscle tissues of the gastric fundus generated on-relaxations and off-contractions with the frequency of 1–16 Hz. The on-responses induced a relaxation, partially mediated by the release of nitric oxide (NO) because addition of L-NNA turned the relaxations into cholinergically mediated contractions. The off-contractions were also cholinergically mediated as they disappeared under non-adrenergic, non-cholinergic (NANC) conditions using atropine and guanethidine. In fundic strips, motilin and EM-A induced on-relaxation and off-contraction and both motilin (1 µmol/L) and EM-A (100 µmol/L) may significantly increased on-response and reduced off-response (P | |||||||||
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