Ghrelin induces fasted motor activity of the gastrointestinal tract in conscious fed rats
Ghrelin induces fasted motor activity of the gastrointestinal tract in conscious fed rats
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DOI：
10.1113/jphysiol.2003.040600
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发表时间：
2003-07-01
影响因子：
5.5
通讯作者：
Fujimiya, M
中科院分区：
文献类型：
--
作者：
Fujino, K;Inui, A;Fujimiya, M
胃促生长素是一种新发现的产氧肽，原产于胃。然而，其在调节进食和禁食消化道运动活动中的作用尚不完全清楚。在本研究中，我们观察了脑室内和静脉注射胃饥饿素对自由运动意识大鼠胃和十二指肠生理进食和禁食运动活动的影响。正常喂养大鼠胃胃饥饿素和静脉注射胃饥饿素均可引起十二指肠空腹运动，迷走神经损伤大鼠胃和十二指肠均可引起空腹运动。体外注射和静脉注射胃饥饿素的作用均被相同途径给药的生长激素分泌受体（GHS-R）拮抗剂阻断，也被脑内神经肽Y （NPY）的免疫中和作用阻断。静脉注射GHS-R拮抗剂对迷走神经损伤大鼠胃饥饿素的作用没有影响。注射GHS-R拮抗剂可阻断迷走神经切断大鼠胃和十二指肠的空腹运动活动，但对正常大鼠的空腹运动活动无影响。低胃内pH抑制胃饥饿素的作用。目前的结果表明，胃饥饿素参与调节胃和十二指肠的空腹运动活动。外周胃饥饿素可能通过迷走神经传入神经元上的胃饥饿素受体激活脑内NPY神经元，从而引起运动活动的加速。一旦大脑机制。经迷走神经截除，胃饥饿素可能主要通过胃和十二指肠上的胃饥饿素受体参与调节空腹运动活动。胃促生长素诱导快速运动的作用受胃内pH值的强烈影响；低pH值抑制作用。
Ghrelin is a newly discovered orexigenic peptide originating from the stomach. However, its action in regulating the fed and fasted motor activity of the digestive tract is not fully understood. In the present study, we examined the effects of intracerebroventricular (I.C.V.) and intravenous (I.V.) injection of ghrelin on the physiological fed and fasted motor activities in the stomach and duodenum of freely moving conscious rats. I.C.V. and I.V. injection of ghrelin induced fasted motor activity in the duodenum in normal fed rats, while I.V. injection of ghrelin induced fasted motor activity in both the stomach and duodenum in vagotomized rats. The effects of I.C.V. and I.V. injected ghrelin were blocked by growth hormone secretagogue receptor (GHS-R) antagonist given by the same route and also blocked by immunoneutralization of neuropeptide Y (NPY) in the brain. The effects of I.V. injected ghrelin were not altered by I.C.V. injection of GHS-R antagonist in vagotomized rats. Injection of GHS-R antagonist blocked the fasted motor activity in both the stomach and duodenum in vagotomized rats but did not affect the fasted motor activity in normal rats. Low intragastric pH inhibited the effect of ghrelin. The present results indicate that ghrelin is involved in regulation of fasted motor activity in the stomach and duodenum. Peripheral ghrelin may induce the fasted motor activity by activating the NPY neurons in the brain, probably through ghrelin receptors on vagal afferent neurons. Once the brain mechanism is. eliminated by truncal vagotomy, ghrelin might be primarily involved in the regulation of fasted motor activity through ghrelin receptors on the stomach and duodenum. The action of ghrelin to induce fasted motor activity is strongly affected by intragastric pH; low pH inhibits the action.