Ecabet sodium raises plasma levels of calcitonin gene-related peptide and substance P in healthy humans

Ecabet sodium induces neuronal nitric oxide synthase-derived nitric oxide synthesis and gastric adaptive relaxation in the human stomach

BACKGROUND

Gastric adaptive relaxation (GAR) is a major factor of functional dyspepsia (FD). Nitric oxide (NO) could be the key molecule responsible for GAR. We previously reported that the physiological gastric reservoir ability can be evaluated by measuring the cross-sectional area of the proximal stomach by abdominal ultrasonography (US). Ecabet sodium (ES), a gastro-protective antiulcer agent, has been shown to improve symptoms in FD patients. We examined the effects of ES on GAR in humans and on NO synthesis in vitro.

METHODS

GAR was measured by US in 14 subjects, 8 of whom had a pressure sensor inserted into their stomach, after treatment with ES, placebo, or no drugs. NO was measured in SH-SY 5Y cells using a fluorescent indicator. Neuronal, endothelial and inducible NO synthase (nNOS, eNOS and iNOS, respectively) expressions were examined in SH-SY 5Y cells by Western blotting.

RESULTS

Compared to placebo, ES induced significantly greater dilatation of the proximal stomach after the subjects drank 300-400 ml water (P < 0.05). After ES intake, the intragastric pressure did not change significantly, but it tended to be lower (n = 8; P = 0.15). ES increased NO production and nNOS expression, but not iNOS or eNOS expression, in SH-SY 5Y cells in vitro. Pretreatment with non-selective NO synthase (NOS) inhibitor, but not with iNOS-selective inhibitor, reduced NO production by ES.

CONCLUSION

ES may promote GAR in humans through nNOS-related NO; therefore, it may be useful for patients with FD.

G cells and gastrin in chronic alcohol-treated rats

Numerous reports have described gastric mucosal injury in rats treated with high ethanol concentrations. However, to the best of our knowledge, ultrastructural characteristics of G cells and antral gastrin levels have not been previously reported, either in rats that chronically consumed alcohol or in human alcoholics. The goal of this study was to examine the effect of ethanol consumption (8.5 g/kg) over a 4-month period, under controlled nutritional conditions, on antral and plasma levels of gastrin, ultrastructure of G cells, morphometric characteristics of G cells by stereological methods, and analysis of endocrine cells in the gastric mucosa by immunohistochemistry. The chronic alcohol consumption resulted in a nonsignificant decrease in gastrin plasma levels and unchanged antral gastrin concentrations. A slightly damaged glandular portion of the gastric mucosa and dilatation of small blood vessels detected by histological analysis, suggests that ethanol has a toxic effect on the mucosal surface. Chronic alcohol treatment significantly decreased the number of antral G cells per unit area, and increased their cellular, nuclear, and cytoplasmatic profile areas. In addition, the volume density and diameter of G-cell granules, predominantly the pale and lucent types, were increased, indicating inhibition of gastrin release. Ethanol treatment also decreased the number of gastric somatostatin-, serotonin-, and histamine-immunoreactive cells, except the somatostatin cells in the pyloric mucosa, as well as both G: D: enterochromaffin cells (EC) cell ratios in the antrum and D: ECL cell ratios in the fundus. These results indicate that the change of morphometric parameters in G cells may be related to cellular dysfunction. Our findings also suggest that regulation of G-cell secretion was not mediated by locally produced somatostatin in ethanol-consuming rats, but may involve gastric luminal content and/or neurotransmitters of gastric nerve fibers.

Effects of itopride hydrochloride on plasma gut-regulatory peptide and stress-related hormone levels in healthy human subjects

Itopride hydrochloride (itopride), a gastrokinetic drug, has recently been evaluated for its clinical usefulness in functional dyspepsia. We investigated effects of itopride on human plasma gastrin-, somatostatin-, motilin-, and cholecystokinin (CCK)-like immunoreactive substances (IS); adrenocorticotropic hormone (ACTH)-immunoreactive substances (IS), and cortisol under stress conditions in healthy subjects. A single administration of itopride caused significant increases in plasma somatostatin- and motilin-IS levels compared to placebo. Itopride significantly decreased plasma CCK-IS, and suppressed the ACTH-IS level compared to placebo. We hypothesize that itopride may have an accelerating gastric emptying effect, and a modulatory effect on the hypothalamo-pituitary-adrenal axis and autonomic nervous functions. These effects might be beneficial in stress-related diseases, suggesting that itopride has clinicopharmacological activities.