Identification of Drinking Center and Its regulatory substances isolated from the Eel Gut

为了补充海水中的利斯，鳗鱼饮用海水并通过肠道吸收。然而，肠道不能直接从海水中吸收水分。当高浓度NaCl进入肠道时，鳗鱼停止饮水，这是由于肠内Cl^- Na^+本身增强了饮水行为。Na^+或Cl^-到达肠道后20 min，饮水行为发生改变。因此，我们推测肠道分泌的某些激素类物质可能对饮酒行为有调节作用。当血管紧张素II（ANGII），组胺（HA），serotomin（5-HT），carbochol，异丙肾上腺素，催乳素，或P物质注入到后主静脉，饮酒被抑制。另一方面，心房钠尿肽（ANP）、血管生成素、生长抑素、苯肾上腺素、血管活性肠肽（VIP）、胆囊收缩素（CCK-8）、肽YY和鳗鱼肠五肽（EIPP）使饮水停止。因为所有这些试剂都是从血液中起作用的， 关于我们 推测脑内的墨水中心可能是脑室周围器官的一部分，此处不存在血脑屏障。腹腔注射伊文思蓝后，延髓背侧部、小脑腹侧部和血管囊基底部均消失，表明这些部位无血脑屏障。我们还观察到HA和5-HT的作用是通过ANGII实现的，提示ANGII是直接作用于脑的候选者之一。因此，在接下来的实验中，将ANGI-荧光素应用于鳗鱼脑的切片。在延髓背侧部和血管囊基部观察到特异性荧光。延髓背侧部和血管囊基部可能是鳗鱼饮水中枢的一部分。虽然从鳗鱼肠中分离的EIPP抑制饮水行为，但用高浓度C^-灌流肠道后，HPLC在孵育液中未检测到EIPP。少

To compensate for water liss in sea water, eels drink the sea water and absorbed it through the intestine. However, the intestine can not absorb water from the sea water directly. If highly concentrated NaCl enters into the intestine, eels stopped the drinking, which was due to luminal Cl^- Na^+ itself enhanced the drinking behavior. The drinking behavior was altered 20 min after Na^+ or Cl^- reached to the intestine. Therefore, we expected some hormonal substances secreted from the intestine might regulate drinking behavior. When angiotensin II (ANGII), histamine (HA), serotomin (5-HT), carbochol, isoproterenol, prolactin, or substance P was injected into the posterior cardinal vein, the drinking was depressed. On the other hand, atrial natriuretic peptide (ANP), vasotocin, smatostatin, phenylephrine, vasoactive intestinal peptide (VIP), cholecystokinin (CCK8), peptide YY,and eel intestinal pentapeptide (EIPP) stopped the drinking. Because all these reagents act from the blood, the dr … More inking center was suspected to be a part of the circumventricular organs, where no blood-brain barrier exist. When Evans Blue was injected intraperitoneally, dorsal part of the medulla oblongata, ventral part of the cerebelum and basal part of the saccus vasculosus in the brain were atained, indicating absence of blood-brain barrier in these areas. We also observed that the effects of HA and 5-HT were via ANGII,suggesting that ANGII is one of candidates which act directly on the brain. Therefore, in the next experiments, ANGI-fluorescen was applied to the section of the eel brain. Specific fluorescence was observed at the dorsal part of the medulla oblongata and at the basal part of the saccus vasculosus. Altogether, the dorsal part of the medulla oblongata and the basal part of the saccus vasculosus may be a part of drinking center in eels. Although EIPP isolated from eel intestine depressed drinking behavior, EIPP was not detected in the incubation medium by HPLC after perfusing the intestine with high concentrated C^-. Less