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

为了弥补海水中的水分不足，鳗鱼喝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进入肠道后，鳗鱼停止饮水，这是由于肠道内Cl^- Na^+本身增强了鳗鱼的饮水行为。Na^+或Cl^-到达肠道20分钟后，饮酒行为发生改变。因此，我们预计肠道分泌的一些激素物质可能调节饮酒行为。当主后静脉注射血管紧张素II （ANGII）、组胺（HA）、血清素（5-HT）、碳水化合物、异丙肾上腺素、催乳素或P物质时，饮酒受到抑制。而心房利钠肽（ANP）、血管催产素、抑素、苯肾上腺素、血管活性肠肽（VIP）、胆囊收缩素（CCK8）、YY肽、鳗鱼肠五肽（EIPP）则使小鼠停止饮酒。因为所有这些试剂都是从血液中起作用的，所以More墨水中心被怀疑是心室周围器官的一部分，那里没有血脑屏障存在。腹腔注射Evans Blue时，获得脑延髓背侧、小脑腹侧和血管囊基底部，表明这些区域血脑屏障缺失。我们还观察到HA和5-HT的作用是通过ANGII，这表明ANGII是直接作用于大脑的候选者之一。因此，在接下来的实验中，angi荧光被应用于鳗鱼脑的切片。在延髓背面和血管囊基部观察到特异性荧光。延髓的背侧部分和血管囊的基底部分可能是鳗鱼饮水中枢的一部分。虽然从鳗肠中分离得到的EIPP抑制了鳗的饮酒行为，但用高浓度C^-灌注肠后，高效液相色谱法未检测到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