Regulatory mechanisms of ion and water transport across the eel intestine

离子和水穿过鳗鱼肠道运输的调节机制

基本信息

批准号：
02804062
负责人：
ANDO Masaki
金额：
$ 0.96万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

The NaCl and water absorption across the eel intestine was inhibited by serotonine (5-HT), acetylcholine (ACh) or atrial natriuretic peptide (ANP), ANP being the most potent inhibitor. The effects of ANP were completely abolished after pretreatment with 8BrcGMP, indicating that ANP acts through cGMP synthesis. Similarly, 5-HT seems to activate cAMP synthesis, since the inhibitory effects of 5-HT were significantly reduced after pretreatment with 8BrcAMP. ACh seems to enhance the intracellular Ca^<2+> concentration, however the effect of Ca^<2+> ionophore, ionom-ycin, was not sufficient to mimic the effect of ACh, suggesting involvement of other mediators.When the intestine was stimulated electnically, the Cl^- transport was reduced transiently. The transient response was inhibited by 70% with atropine, a muscarinic ACh antagonist, and ICS-205930, a 5-HT antagonist, indicating that 70% of the effect of field-stimulation is due to release of ACh and 5HT. The remainig 30% must-be due to other regulators.On the other hand, adrenaline (AD) enhanced the NaCl and water absorption after pretreatment with 5-HT and ACh. The effects of AD were completely abolished with yohimbine, alpha_2-receptor antagonist. Moreover, the effects of AD were still observed even in the presence of 8BrCAMP and ionomyein, suggesting that AD acts on a post-cAMP and post-Ca^<2+> process.A novel peptide was also extracted from the eel intestine, but had no effect on the ion and water transport. The eel intestinal pentapeptide (EIPP, H-Gly-Phe-Trp-Asn-Lys-OH) enhanced the contraction of the srnooth muscle in the digestive tract such as esophagus, stomach and intestine.

血清氨酸（5-HT），乙酰胆碱（ACH）或心房亚替耐酸肽（ANP）抑制了整个鳗鱼肠的NaCl和吸水，ANP是最有效的抑制剂。用8BRCGMP预处理后，ANP的作用被完全废除，表明ANP通过CGMP合成起作用。同样，5-HT似乎激活了cAMP的合成，因为用8brcamp预处理5-HT的抑制作用显着降低。 ACH似乎可以增强细胞内Ca^<2+>浓度，但是Ca^<2+>离子载体（Ionom-Ycin）的影响不足以模仿ACH的影响，这表明其他介体的参与。当肠道刺激肠道刺激时，Cl^ - Cl^ - 转运均能暂时减少。阿托品，毒蕈碱ACH拮抗剂和5-HT拮抗剂ICS-205930抑制了70％的瞬态反应，表明田间刺激的效果的70％是由于ACH和5HT的释放所致。剩余的30％必须是由于其他调节剂。另一方面，肾上腺素（AD）可以通过5-HT和ACH进行预处理后增强NaCl和吸水。 Yohimbine，Alpha_2受体拮抗剂完全消除了AD的作用。此外，即使在8 Brcamp和Ionymyein存在下，AD的效果仍然被观察到，这表明AD作用于训练后和Ca^<2+>过程。也从鳗鱼肠中提取了一种新型的肽，但对离子和水的运输没有影响。鳗鱼肠五肽（EIPP，H-Gly-Phe-phe-trp-asn-Lys-OH）增强了消化道中srnooth肌肉的收缩，例如食道，胃和肠道。