Correlation of 5-hydroxytryptamine synthesis and secretion to endocrinal secretion of atrial natriuretic polypeptide in enterochromaffin cells of rat gastric mucosa / 中国组织工程研究

ABSTRACT

BACKGROUND: Previous researches have proved that both atrial natriuretic polypeptide (ANP) and 5-hydroxytryptamine (5-HT) exist in the same endocrine granule of enterochromaffin cell (EC). However, whether ANP may promote or inhibit synthesis and secretion of 5-HT needs to be further studied. OBJECTIVE: To investigate the effect of ANP on synthesis and secretion of 5-HT in EC of rat gastric mucosa.DESIGN: Randomized controlled animals study.SETTING: Immunology Laboratory, Chengde Medical College. MATERIALS This study was performed at the Immunology Laboratory, Chengde Medical College from October 2004 to July 2007. Forty adult male Wistar rats were provided by the Experimental Animal Center of Chengde Medical College. The experiment was in accordance with animal ethics standards. ANP, 5-HT antibody and serum were provided by Santa Cruz Biotechnology Company, USA.METHODS: Forty rats were randomly into endocrine and exocrine groups, and rats in the two groups were sub-grouped into control and experimental groups with 10 in each group. ANP (28 μg, 14 mg/L) was directly injected into the stomach to mimic ANP luminal secretion and ANP (14 μg, 14 mg/L) was directly injected into the sublingual vein to mimic ANP endocrinal secretion. In above condition, 5-HT immunoreactive positive cell was displayed by using immunohistochemistry technique, numerical density (Nv) of endocrine granule (SG) was counted by using electron microscopic morphometry, and 5-HT level in the serum was measured by using HPLC-ECD technique. And then, the results were compared to the control group. MAIN OUTCOME MEASURES: Effects of ANP on density of 5-HT immunoreactive positive cell, numerical density (Nv) of SG and 5-HT level in the serum. RESULTS: Effect of luminal and endocrine ANP on the 5-HT secretion The density of immunoreactive positive cell and the numerical density (Nv) of SG were significantly increased by luminal and endocrine ANP (P＜0.05), while 5-HT level in serum was significantly reduced by luminal and endocrine ANP (P＜0.05). CONCLUSION: Luminal and endocrinal ANP can inhibit 5-HT release of gastric mucosa but may not change or enhancement its synthesis in rat.