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Motilin (26-47), human, porcine 是一种内源性的 motilin 受体激动剂，在中国仓鼠卵巢细胞中，Ki 值和 EC50 值分别为 2.3 nM 和 0.3 nM。

Motilin (26-47), human, porcine is an endogenous motilin receptor ligand with Ki and EC50 of 2.3 nM and 0.3 nM in a Chinese hamster ovary cell line.

胃动素是一种肽，被用作细胞生物学，药理学和生物化学领域的研究工具。它是胃动素受体的激活剂，并已显示与配体门控离子通道结合。胃动素也被证明可以抑制高压激活的钙通道的活性。

Motilin is a peptide that is used as a research tool in the fields of cell biology, pharmacology, and biochemistry. It is an activator of the motilin receptor and has been shown to bind to ligand-gated ion channels. Motilin has also been shown to inhibit the activity of high-voltage activated calcium channels.

刺激肠道平滑肌收缩的肠肽。胃动素受体尚未克隆，但胃动素受体激动剂似乎是治疗运动障碍的有效促动力剂。

Intestinal peptide that stimulates contraction of gut smooth muscle. The motilin receptor has not been cloned yet, but motilin-receptor agonists appear to be potent prokinetic agents for the treatment of dysmotility disorders.

胃动素(Motilin)的定义

胃动素是十二指肠粘膜内分泌细胞产生的一种激素，有助于调节消化道的运动。

Motilin is a hormone produced from endocrine cells of the duodenal mucosa to help regulate motility of the digestive tract.

胃动素(Motilin)的发现

当布朗将碱性溶液引入狗的十二指肠引起强烈的胃收缩时，他发现了胃动素。布朗等人，。预测碱可以释放刺激物以激活运动活动或阻止抑制性激素的分泌。他们分离出多肽作为羧甲基纤维素上分泌素纯化的副产物。他们将这种多肽命名为“胃动素”【1】。

Motilin was discovered by Brown when he introduced alkaline solution into duodenum of dogs which caused strong gastric contractions. Brown et al,. predicted that alkali could either release stimulus to activate motor activity or prevent the secretion of inhibitory hormone. They isolated polypeptide as a byproduct from purification of secretin on carboxymethyl cellulose. They named this polypeptide “Motilin” 【1】.

胃动素(Motilin)的结构特征

胃动素具有22个氨基酸，分子量为2.6 kDa。胃动素基因具有不寻常的结构，其中一个小的生物活性肽编码在两个不同的外显子上。通过Northern杂交分析检查人和非人灵长类动物胃动素基因的表达表明，它在许多胃肠道和胃肠外组织中表达【2】。胃动素的氨基酸序列为：Phe-Val-Pro-Ile-Phe-Thr-Tyr-Gly-Glu-Leu-Gln-Arg-Met-Gln-Glu-Lys-Glu-Arg-Asn-Lys-Gly-Gln。13C动力学清楚地表明，胃动素具有很大程度的局部柔韧性，并与bicelle相互作用，显示出与膜结合的肽的运动特性。相比之下，中性双细胞中的胃动素似乎结构不太规整，更具灵活性。该结构揭示了Glu-9和Lys-20之间的有序α螺旋构象。N末端的结构也很好，其转弯类似于经典的β转弯【3】。

Motilin has 22 amino acids and molecular weight of 2.6 kDa. The motilin gene has an unusual structure in which a small bioactive peptide is encoded on two distinct exons. Examination of the expression of the human and nonhuman primate motilin gene by Northern hybridization analysis indicates that it is expressed in a number of gastrointestinal and extragastrointestinal tissues 【2】. The sequences of amino acids of motilin is: Phe-Val-Pro-Ile-Phe-Thr-Tyr-Gly-Glu-Leu-Gln-Arg-Met-Gln-Glu-Lys-Glu-Arg-Asn-Lys-Gly-Gln. The 13C dynamics clearly show that motilin has a large degree of local flexibility and interacts with the bicelle, displaying motional properties of a peptide bound to a membrane. In comparison, motilin in neutral bicelles seems less structured and more flexible. The structure reveals an ordered alpha-helical conformation between Glu-9 and Lys-20. The N-terminus is also well structured with a turn resembling that of a classical beta-turn 【3】.

胃动素(Motilin)的作用机制

胃动素是肽家族的成员，该肽家族包括生长素释放肽，其cDNA还编码肽obestatin。胃动素对生理学家来说是一种迷人的激素。它与家庭成员生长素释放肽和obestatin相互作用。胃动素受体激动剂或拮抗剂可能很快成为临床医生改善消化功能障碍的治疗手段的一部分【4】。还确定了迷走神经对免疫反应性（IR）胃动素循环水平的影响。五只杂种狗在小肠中配备了长期植入的电极，以记录肌电活动。在膈肌水平的躯干迷走神经切断术之前和之后，研究了空腹，餐后和胰岛素输注期间IR胃动素的释放。当在手术后至少两周进行测试时，迷走神经切片保持小肠的运动模式和IR胃动素的分泌不变。迷走神经切断术后仍观察到与消化间期肌电复合物III期相关的IR胃动素的周期性增加，并且它们仍然被喂养或胰岛素所消除。狗的远端迷走神经切断术不会长期改变胃动素的释放【5】。

Motilin is a member of the peptide family that includes ghrelin whose cDNA also encodes peptide, obestatin. Motilin is a fascinating hormone for the physiologist. It interacts with the family member ghrelin and with obestatin. Motilin-receptor agonists or antagonists could soon be part of the therapeutic arsenal of the clinician to improve digestive dysmotility 【4】. The influence of the vagus on the circulating levels of immunoreactive (IR) motilin was also determined. Five mongrel dogs were equipped with chronically implanted electrodes in the small intestine to record the myoelectrical activity. The release of IR motilin during fasting, after a meal, and during an infusion of insulin was studied before and after truncal vagotomy at the diaphragmatic level. When tested at least two weeks after the operation, the motility pattern of the small intestine and the secretion of IR motilin remained unaltered by vagal section. Cyclic increases in IR motilin associated with phase III's of the interdigestive myoelectric complexes were still observed after vagotomy, and they were still abolished by feeding or by insulin. The release of motilin is not chronically altered by distal vagotomy in dogs 【5】.

胃动素(Motilin)的功能

胃动素的主要功能是增加胃肠运动的迁移性肌电复合物成分并刺激胃蛋白酶的产生。两餐之间分泌的高水平胃动素进入血液，刺激眼底和胃窦的收缩，加速胃排空。然后它收缩胆囊并增加食管下括约肌的挤压压力。胃动素增加胰腺多肽和生长抑素的释放【6】。迷走神经和胃动素都与空腹迁移运动复合体的III期开始有关。监测下食管括约肌，胃和上小肠的腔内压力以及血浆胃动素水平。狗的结果表明，虽然上消化道的自发性II期运动和下食管括约肌和胃的III期活动依赖于迷走神经介导的兴奋性途径，但小肠的自发性和诱导性III期运动活动依赖于非迷走神经胆碱能神经支配。猪胃动素诱导的犬胃动素释放主要由非迷走神经胆碱能（毒蕈碱）途径介导，迷走神经非胆碱能和非迷走神经非胆碱能机制的贡献较小。胃动素可以调节由先前存在的神经兴奋产生的运动【7】。

The main function of motilin is to increase the migrating myoelectric complex component of gastrointestinal motility and stimulate the production of pepsin. A high level of motilin secreted between meals into the blood, stimulates the contraction of the fundus and antrum and accelerates gastric emptying. It then contracts the gallbladder and increases the squeeze pressure of the lower esophageal sphincter. Motilin increases the release of pancreatic polypeptide and somatostatin 【6】. Both the vagus nerve and motilin have been implicated in the initiation of phase III of the fasting migrating motor complex. Intralumenal pressures of the lower esophageal sphincter, stomach, and upper small intestine, and plasma motilin levels were monitored. Results in dogs indicate that while spontaneous phase II motility in the upper gastrointestinal tract and phase III activity in the lower esophageal sphincter and stomach are dependent on vagally mediated excitatory pathways, spontaneous and induced phase III motor activity in the small intestine are dependent on nonvagal cholinergic innervation. Canine motilin release induced by porcine motilin is mediated primarily by a nonvagal cholinergic (muscarinic) pathway, with minor contributions from vagal noncholinergic, and nonvagal noncholinergic mechanisms. Motilin may modulate motility produced by preexisting neural excitation   【7】.

胃动素(Motilin)的相关文献

1. Brown JC, Cook MA, Dryburgh JR (1973). Motilin, a gastric motor activity stimulating polypeptide: the complete amino acid sequence. Canadian journal of biochemistry, 51(5): 533–557.

2. Daikh DI, Douglass JO, Adelman JP (1989). Structure and expression of the human motilin gene. DNA., 8 (8):615–621.

3. Andersson A, Mäler L (2002). NMR solution structure and dynamics of motilin in isotropic phospholipid bicellar solution. J. Biomol NMR., 24 (2):103–112.

4. Poitras P, Peeters TL (2008).Motilin. Curr Opin Endocrinol Diabetes Obes., 15(1):54–57.                      

5. Lemoyne M, Wassef R, Tassé D, Trudel L, Poitras P (1984). Motilin and the vagus in dogs. Canadian journal of physiology and pharmacology., 62(9):1092–1096.

6. Book: Williams, Robert L. (1981). Textbook of endocrinology., (6th ed.). Philadelphia: Saunders.

7. Hall KE, Greenberg GR, El-Sharkawy TY, Diamant NE (1984). Relationship between porcine motilin-induced migrating motor complex-like activity, vagal integrity, and endogenous motilin release in dogs. Gastroenterology, 87 (1): 76–85.