Ferrier L, Segain J P, Pacaud P, Cherbut C, Loirand G, Galmiche J P, Blottière H M
Centre de Recherche en Nutrition Humaine, CRI INSERM 95-08, CHU-Hôtel Dieu, BP 1005, 44035 Nantes cedex 01, France.
Gut. 2000 Mar;46(3):370-5. doi: 10.1136/gut.46.3.370.
Peptide YY (PYY) is involved in the regulation of several gut functions, including secretion and motility. It exerts its effects through a family of six receptors, commonly named the Y receptor family.
To characterise the effects of PYY on strips of rat proximal colon in vitro, and to determine the pathways and receptors involved.
Contractions of strips removed from the muscle layer of rat proximal colon were recorded under isometric conditions, using PYY, Y receptor agonists and antagonists, and nerve blockers. Reverse transcription-polymerase chain reaction was also performed to detect the presence of mRNA coding for Y receptors. Finally, smooth muscle cells were isolated to estimate the cell length and intracellular Ca(2+) concentration in the presence and absence of PYY.
PYY, neuropeptide Y (NPY), pancreatic polypeptide (PP) and [Leu31,Pro34]NPY induced a dose dependent contraction of strips from proximal colon. Tetrodotoxin partially inhibited the PYY and NPY induced contractions, and strongly inhibited the PP induced contraction. Specific antagonists showed the involvement of cholinergic nicotinic receptors and NK1 receptor. BIBP 3226, a specific Y1 antagonist, did not modify the colonic smooth muscle response to PYY, whereas blocking L-type Ca(2+) channels with D-600 abolished its effects. Moreover, PYY induced an increase in intracellular Ca(2+) concentration, associated with a reduction in cell length. mRNA encoding Y1 and Y4 receptors were detected in the muscle strips.
These findings suggest that PYY stimulates colonic contractile activity in vitro through (a) a nervous Y4 dependent pathway and (b) a pathway involving a potential new receptor on myocytes.
肽YY（PYY）参与多种肠道功能的调节，包括分泌和蠕动。它通过一个由六个受体组成的家族发挥作用，该家族通常被称为Y受体家族。
在体外研究PYY对大鼠近端结肠条的影响，并确定其涉及的途径和受体。
在等长条件下记录从大鼠近端结肠肌层取出的结肠条的收缩情况，使用PYY、Y受体激动剂和拮抗剂以及神经阻滞剂。还进行了逆转录-聚合酶链反应以检测编码Y受体的mRNA的存在。最后，分离平滑肌细胞以评估在有和没有PYY的情况下细胞长度和细胞内Ca(2+)浓度。
PYY、神经肽Y（NPY）、胰多肽（PP）和[Leu31,Pro34]NPY诱导近端结肠条产生剂量依赖性收缩。河豚毒素部分抑制PYY和NPY诱导的收缩，并强烈抑制PP诱导的收缩。特异性拮抗剂显示胆碱能烟碱受体和NK1受体参与其中。特异性Y1拮抗剂BIBP 3226不改变结肠平滑肌对PYY的反应，而用D-600阻断L型Ca(2+)通道则消除其作用。此外，PYY诱导细胞内Ca(2+)浓度增加，同时细胞长度减少。在肌条中检测到编码Y1和Y4受体的mRNA。
这些发现表明，PYY在体外通过（a）一条依赖于神经Y4的途径和（b）一条涉及心肌细胞上潜在新受体的途径刺激结肠收缩活性。
