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，鳗鱼喝下海水并通过肠道吸收。然而，肠道不能直接吸收海水中的水。如果高浓度的氯化钠进入肠道，鳗鱼停止了摄食，这是由于流明的Cl~+-Na~+本身增强了鳗鱼的摄食行为。Na~(++)或Cl~(-)到达肠道20min后，饮酒行为发生改变。因此，我们预计肠道分泌的某些荷尔蒙物质可能会调节饮酒行为。当血管紧张素II(AngII)、组胺(HA)、5-羟色胺(5-HT)、Carchol、异丙肾上腺素、催乳素或P物质被注入后基静脉时，饮酒受到抑制。另一方面，心钠素(ANP)、血管催产素、生长抑素、苯肾上腺素、血管活性肠肽(VIP)、胆囊收缩素(CCK8)、YY肽和鳗鱼肠五肽(EIPP)停止饮用。因为所有这些试剂都是从血液中起作用的，…博士更多的墨汁中心被怀疑是脑室周围器官的一部分，那里不存在血脑屏障。经腹膜腔注射伊文思蓝后，脑内延髓背侧、小脑腹侧和血管囊基底部均可见，提示这些部位无血脑屏障。我们还观察到HA和5-羟色胺的作用是通过血管紧张素Ⅱ实现的，这表明血管紧张素Ⅱ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-荧光素被应用到鳗鱼脑的切片上。在延髓的背侧和血管球囊的基底部观察到特殊的荧光。总之，鳗鱼延髓的背侧部分和血管球囊的基底部可能是其饮水中枢的一部分。虽然从鳗鱼肠道中分离到的EIPP抑制了小鼠的饮水行为，但用高浓度C^-灌流肠道后，在孵育液中未检测到EIPP。较少

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