Comparative Animal Pharmacology, Department of Veterinary Science, Rakuno Gakuen University, Ebetsu, Japan.
Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, Suita, Japan.
Front Endocrinol (Lausanne). 2021 Aug 23;12:700884. doi: 10.3389/fendo.2021.700884. eCollection 2021.
Motilin, produced in endocrine cells in the mucosa of the upper intestine, is an important regulator of gastrointestinal (GI) motility and mediates the phase III of interdigestive migrating motor complex (MMC) in the stomach of humans, dogs and house musk shrews through the specific motilin receptor (MLN-R). Motilin-induced MMC contributes to the maintenance of normal GI functions and transmits a hunger signal from the stomach to the brain. Motilin has been identified in various mammals, but the physiological roles of motilin in regulating GI motility in these mammals are well not understood due to inconsistencies between studies conducted on different species using a range of experimental conditions. Motilin orthologs have been identified in non-mammalian vertebrates, and the sequence of avian motilin is relatively close to that of mammals, but reptile, amphibian and fish motilins show distinctive different sequences. The MLN-R has also been identified in mammals and non-mammalian vertebrates, and can be divided into two main groups: mammal/bird/reptile/amphibian clade and fish clade. Almost 50 years have passed since discovery of motilin, here we reviewed the structure, distribution, receptor and the GI motility regulatory function of motilin in vertebrates from fish to mammals.
胃动素由上消化道黏膜的内分泌细胞产生，是胃肠（GI）运动的重要调节剂，通过特异性胃动素受体（MLN-R）在人类、犬和猪囊尾蚴的胃中介导消化间期移行性复合运动（MMC）的第三期。胃动素诱导的 MMC 有助于维持正常的 GI 功能，并将饥饿信号从胃传递到大脑。胃动素已在各种哺乳动物中被鉴定出来，但由于在不同物种中使用一系列实验条件进行的研究结果不一致，胃动素在调节这些哺乳动物的 GI 运动中的生理作用尚不清楚。非哺乳动物脊椎动物中已鉴定出胃动素的同源物，并且禽类胃动素的序列与哺乳动物的序列相对接近，但爬行动物、两栖动物和鱼类胃动素显示出独特的不同序列。MLN-R 也已在哺乳动物和非哺乳动物脊椎动物中被鉴定出来，可分为两大类：哺乳动物/鸟类/爬行动物/两栖动物群和鱼类群。自从发现胃动素以来已经过去了将近 50 年，在这里我们综述了从鱼类到哺乳动物的脊椎动物中胃动素的结构、分布、受体和对 GI 运动的调节功能。
