title: Effects of ghrelin on gastric distention sensitive neurons in the arcuate nucleus of hypothalamus and gastric motility in diabetic rats.
abstract: This study was performed to observe the effects of ghrelin on the activity of gastric distention (GD) sensitive neurons in the arcuate nucleus of hypothalamus (Arc) and on gastric motility in vivo in streptozocin (STZ) induced diabetes mellitus (DM) rats. Electrophysiological results showed that ghrelin could excite GD-excitatory (GD-E) neurons and inhibit GD-inhibitory (GD-I) neurons in the Arc. However, fewer GD-E neurons were excited by ghrelin and the excitatory effect of ghrelin on GD-E neurons was much weaker in DM rats. Gastric motility research in vivo showed that microinjection of ghrelin into the Arc could significantly promote gastric motility and it showed a dose-dependent manner. The effect of ghrelin promoting gastric motility in DM rats was weaker than that in normal rats. The effects induced by ghrelin could be blocked by growth hormone secretagogue receptor (GHSR) antagonist [d-Lys-3]-GHRP-6 or BIM28163. RIA and real-time PCR data showed that the levels of ghrelin in the plasma, stomach and ghrelin mRNA in the Arc increased at first but decreased later and the expression of GHSR-1a mRNA in the Arc maintained a low level in DM rats. The present findings indicate that ghrelin could regulate the activity of GD sensitive neurons and gastric motility via ghrelin receptors in the Arc. The reduced effects of promoting gastric motility induced by ghrelin could be connected with the decreased expression of ghrelin receptors in the Arc in diabetes. Our data provide new experimental evidence for the role of ghrelin in gastric motility disorder in diabetes.
authors: Department of Pathophysiology, Medical College of Qingdao University, Qingdao 266021, China. Electronic address: xu.luo@163.com.
authors: Luo
authors: L
authors: Xu
authors: Zhuling
authors: Z
authors: Qu
authors: Feifei
authors: F
authors: Guo
authors: Mingjie
authors: M
authors: Pang
authors: Shengli
authors: S
authors: Gao
authors: Hai
authors: H
authors: Zhu
authors: Fang
authors: F
authors: Gu
authors: Xiangrong
authors: X
authors: Sun
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D005753:Gastric Mucosa / Q000378:metabolism*; D054439:Ghrelin / Q000378:metabolism / Q000494:pharmacology*; D007031:Hypothalamus / Q000187:drug effects; D009474:Neurons / Q000187:drug effects; D036361:Peptide Hormones / Q000494:pharmacology; D051381:Rats; D054440:Receptors, Ghrelin / Q000378:metabolism; D013270:Stomach / Q000187:drug effects / Q000502:physiology; D013272:Stomach Diseases / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D013311:Streptozocin / Q000378:metabolism
chemical_list: C492347:BIM28163; D054439:Ghrelin; D036361:Peptide Hormones; D054440:Receptors, Ghrelin; D013311:Streptozocin
keywords: Arcuate nucleus of hypothalamus; DGP; DM; Diabetes mellitus; GAPDH; GD; GD-E neurons; GD-I neurons; GHSR; Gastric distention sensitive neurons; Gastric motility; Ghrelin; Rats; diabetes mellitus; diabetic gastroparesis; gastric distention; gastric distention excitatory neurons; gastric distention inhibitory neurons; glyceraldehyde-3-phosphate dehydrogenase; growth hormone secretagogue receptor