Contractile effects of ghrelin-related peptides on the chicken gastrointestinal tract in vitro
Contractile effects of ghrelin-related peptides on the chicken gastrointestinal tract in vitro
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DOI：
10.1016/j.peptides.2006.10.012
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发表时间：
2007-03-01
期刊：
影响因子：
3
通讯作者：
Taneike, Tetsuro
中科院分区：
文献类型：
--
作者：
Kitazawa, Takio;Kaiya, Hiroyuki;Taneike, Tetsuro
胃饥饿素（Ghrelin）是生长激素促分泌受体（GHS-R）的内源性配体，刺激哺乳动物生长激素（GH）的释放、食物摄入和胃肠运动。在鸡体内也发现了胃饥饿素，但这种肽会抑制鸡的食物摄入。我们研究了胃饥饿素和相关肽对离体鸡胃肠道收缩力的影响。在胃饥饿素相关肽（1 μ M的大鼠胃饥饿素、人胃饥饿素、鸡胃饥饿素和生长激素释放肽-6 (GHRP-6)）中，只有鸡胃饥饿素对鸡胃肠道收缩有效。去酰化鸡胃饥饿素是无效的，这表明鸡胃饥饿素Ser(3)残基的辛烷化是诱导收缩的必要条件。鸡胃饥饿素诱导的收缩幅度具有区域特异性：大肠和小肠收缩幅度最大，食道和前心室收缩幅度中等，小肠收缩幅度较弱。河豚毒素（TTX）对作物对鸡胃饥饿素的收缩反应没有影响，但TTX和阿托品对作物前心室的收缩反应有相同程度的降低。D-Lys(3)-GHRP-6（一种GHS-R拮抗剂）在不影响高k +诱导的鸡胃饥饿素收缩的情况下，引起短暂性收缩并抑制其作用。鸡胃饥饿素增强了电场刺激诱导的胆碱能收缩，而不影响前脑室对沐浴用苯酚的反应。GHS-R在作物（平滑肌）和前脑室（平滑肌和肠神经元）的位置不同。上述结果表明，胃饥饿素对鸡体外胃肠道具有收缩作用，且具有区域特异性。GHS-R对鸡胃饥饿素高度敏感。(c) 2006爱思唯尔公司版权所有。
Ghrelin is an endogenous ligand for growth hormone secretagogue receptor (GHS-R), and it stimulates growth hormone (GH) release, food intake and gastrointestinal motility in mammals. Ghrelin has also been identified in the chicken, but this peptide inhibits food intake in the chicken. We examined the effects of ghrelin and related peptides on contractility of the isolated chicken gastrointestinal tract in vitro. Among ghrelin-related peptides examined (1 mu M of rat ghrelin, human ghrelin, chicken ghrelin and growth hormone releasing peptide-6 (GHRP-6)), only chicken ghrelin was effective on contraction of the chicken gastrointestinal tract. Des-acyl chicken ghrelin was ineffective, suggesting that octanoylation at Ser(3) residue of chicken ghrelin was essential for inducing the contraction. Amplitude of chicken ghrelin-induced contraction was region-specific: highest in the crop and colon, moderate in the esophagus and proventriculus, and weak in the small intestine. The contractile response to chicken ghrelin in the crop was not affected by tetrodotoxin (TTX), but that in the proventriculus was decreased by TTX and atropine to the same extents. D-Lys(3)-GHRP-6 (a GHS-R antagonist) caused a transient contraction and inhibited the effect of chicken ghrelin without affecting the high-K+-induced contraction. Chicken ghrelin potentiated electrical field stimulation-induced cholinergic contraction without affecting the responsiveness to bath-applied carbachol in the proventriculus. The location of GHS-R differs in the crop (smooth muscle) and proventriculus (smooth muscle and enteric neurons). These results indicate that ghrelin has contractile activity on gastrointestinal tract in the chicken in vitro, and the effect was region-specific. The action would be mediated through the GHS-R, which is highly sensitive to chicken ghrelin. (c) 2006 Elsevier Inc. All rights reserved.