Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Neurogastroenterol Motil. 2012 Feb;24(2):e94-102. doi: 10.1111/j.1365-2982.2011.01789.x. Epub 2011 Oct 17.
Orexin-A is a novel peptide that appears to play a role in regulation of gastric acid secretion. However, little is known about sites of its action. In addition, evidences suggest that some of orexin-A neurons respond to glucose. In this study, we address the hypothesis which demonstrates that orexin-A and glucose act in the hypothalamic paraventricular nucleus (PVN) to increase gastric acid secretion and juice volume in pyloric-ligated conscious rats.
Male Wistar rats were implanted with guide canula directed to the PVN. Orexin-A (3-10 μg), glucose (350-750 ng) SB334867 (6-20 μg) were microinjected. The effect of pretreatment with an orexin-1 receptor antagonist, SB334867, on orexin-A and D-glucose induced acid secretion was assessed. Gastric acid secretion was measured using the pylorus-ligation method, and the amount of gastric acid was determined by titration with 0.01 N NaOH to a pH of 7.0.
Intraparaventricular injection of orexin-A or D-glucose stimulated gastric acid secretion in a dose-dependent manner. The PVN injections of orexin-A receptor antagonist, SB334867, were associated with gastric acid secretion decrease and inhibited effects of PVN-injected orexin-A. Orexin-stimulated gastric acid secretion was decreased (~40%) after PVN lesions. Glucose-stimulated gastric acid secretion was also suppressed by intraperitoneal (IP) injection of SB334867. In addition, it was observed that co-injection of orexin-A and glucose at ineffective doses increased gastric secretion significantly.
CONCLUSIONS & INFERENCES: We suggest that orexin-A and glucose effects on the PVN stimulate gastric acid secretion. This stimulatory effect is probably mediated by orexin-1 receptors.
食欲素-A 是一种新型肽，似乎在调节胃酸分泌中发挥作用。然而，人们对其作用部位知之甚少。此外，有证据表明，一些食欲素-A 神经元对葡萄糖有反应。在这项研究中，我们提出了一个假设，即食欲素-A 和葡萄糖在下丘脑室旁核（PVN）中起作用，以增加幽门结扎清醒大鼠的胃酸分泌和胃液量。
雄性 Wistar 大鼠被植入导向 PVN 的引导套管。微注射食欲素-A（3-10μg）、葡萄糖（350-750ng）、SB334867（6-20μg）。评估了食欲素-1 受体拮抗剂 SB334867 预处理对食欲素-A 和 D-葡萄糖诱导的胃酸分泌的影响。采用幽门结扎法测量胃酸分泌量，用 0.01NNaOH 滴定至 pH7.0 确定胃酸量。
脑室旁注射食欲素-A 或 D-葡萄糖可刺激胃酸分泌，呈剂量依赖性。PVN 注射食欲素-A 受体拮抗剂 SB334867 与胃酸分泌减少有关，并抑制 PVN 注射食欲素-A 的作用。PVN 损伤后食欲素刺激的胃酸分泌减少（~40%）。葡萄糖刺激的胃酸分泌也被腹腔内（IP）注射 SB334867 抑制。此外，观察到在无效剂量下共注射食欲素-A 和葡萄糖可显著增加胃液分泌。
我们认为食欲素-A 和葡萄糖对 PVN 的作用刺激胃酸分泌。这种刺激作用可能是通过食欲素-1 受体介导的。
