Previously, pheasant motilin was identified as a 22-amino acid peptide with a sequence of FVPFFTQSDI QKMQEKERIK GQ. In the present study, the distribution of pheasant motilin mRNA was determined and compared with that of ghrelin, a motilin-related peptide. The effects of pheasant motilin on the cognate gastrointestinal (GI) muscle strips were also examined in an in vitro contraction study. The expression of pheasant motilin mRNA was highest in the small intestine (duodenum, jejunum and ileum), moderate in the colon and very low in the brain, lung, heart, pancreas, esophagus, proventriculus, gizzard and caecum, and this distribution was in contrast with that of ghrelin mRNA. Pheasant motilin caused contraction of the cognate GI tract in a region-dependent manner, similar to chicken motilin. The contraction in the small intestine was large and was not affected by atropine. In contrast, contraction in the proventriculus was small and was decreased by atropine. The crop and colon were insensitive to pheasant motilin. Neither GM109 nor MA2029, mammalian motilin receptor antagonists inhibited the contractions of pheasant motilin. Erythromycin was ineffective in the pheasant ileum, although it caused contraction of the rabbit duodenum. These results indicate that pheasant motilin caused contraction through an action on smooth muscles in the small intestine and an action on enteric cholinergic nerves in the proventriculus. This high responsiveness of the small intestine suggests that motilin is a regulator of small intestinal motility in avians, and the characteristic of the motilin receptor in the pheasant might be different from that in mammals, as is that in chickens.

此前，野鸡胃动素被鉴定为具有 FVPFFTQSDI QKMQEKERIK GQ 序列的 22 个氨基酸肽。在本研究中，测定了野鸡胃动素 mRNA 的分布，并与胃动素相关肽 ghrelin 的分布进行了比较。野鸡胃动素对同源胃肠 (GI) 肌肉条的影响也在体外进行了检查。收缩研究。雉鸡胃动素mRNA在小肠（十二指肠、空肠和回肠）中表达最高，在结肠中表达中度，在脑、肺、心脏、胰腺、食道、胃腺、砂囊和盲肠中表达极低，且分布在与 ghrelin mRNA 形成对比。野鸡胃动素以区域依赖性方式引起同源胃肠道收缩，类似于鸡胃动素。小肠收缩大，不受阿托品影响。相比之下，胃腺的收缩很小，并且被阿托品减少。作物和结肠对野鸡胃动素不敏感。哺乳动物胃动素受体拮抗剂 GM109 和 MA2029 均不抑制野鸡胃动素的收缩。红霉素对野鸡回肠无效，虽然它引起了兔子十二指肠的收缩。这些结果表明，野鸡胃动素通过作用于小肠中的平滑肌和作用于胃腺中的肠胆碱能神经而引起收缩。小肠的这种高反应性表明胃动素是鸟类小肠运动的调节剂，而野鸡胃动素受体的特征可能与哺乳动物不同，鸡也是如此。