LEUCOKININS, A NEW FAMILY OF ION-TRANSPORT STIMULATORS AND INHIBITORS IN INSECT MALPIGHIAN TUBULES
LEUCOKININS, A NEW FAMILY OF ION-TRANSPORT STIMULATORS AND INHIBITORS IN INSECT MALPIGHIAN TUBULES
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DOI：
10.1016/0024-3205(89)90362-7
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发表时间：
1989-01-01
期刊：
影响因子：
6.1
通讯作者：
BEYENBACH, KW
中科院分区：
文献类型：
--
作者：
HAYES, TK;PANNABECKER, TL;BEYENBACH, KW
白细胞激肽是从蟑螂Leucophaea maderae的头部分离的八肽。在蟑螂中，它们增加了离体后肠的运动性。令人惊讶的是，合成的白细胞激肽在不同的昆虫和不同的组织中具有生物活性。在分离的马氏管的黄热病蚊子埃及伊蚊，白细胞激肽降低跨上皮电压。这种对电压的影响依赖于细胞外Cl。在分离的马氏管中进一步研究了一种白细胞激肽LK-8的作用，发现其在低浓度（10- 11 M阈值）下抑制跨上皮液体分泌，在高浓度（3.5 × 104）下刺激液体分泌。10-9 M阈值）。总之，对电压的去极化作用和对液体分泌的刺激表明白细胞激肽增加了小管壁的Cl渗透性，从而增加了Cl与Na、K和水的分泌的可用性。七个leucokinins研究的结构-功能比较表明，八肽的活性区域被隔离的C-末端五肽。鉴于白细胞激肽对蟑螂后肠运动的已知作用，我们在蚊子马氏管中的作用发现表明白细胞激肽可能广泛分布于昆虫中，它们可能在各种器官中具有不同的功能。
Leucokinins are octapeptides isolated from heads of the cockroach Leucophaea maderae. In the cockroach they increase motility of the isolated hindgut. Surprisingly, synthetic leucokinins have biological activity in a different insect and in a different tissue. In isolated Malpighian tubules of the yellow fever mosquito Aedes aegypti, leucokinins depolarize the transepithelial voltage. This effect on voltage is dependent on extracellular Cl. One leucokinin, LK-8, the effects of which were studied further in isolated Malpighian tubules, was found to inhibit transepithelial fluid secretion at low concentrations (10-11M threshold), and to stimulate fluid secretion at high concentrations (3.5 .times. 10-9 M threshold). Together, the depolarizing effects on voltage and the stimulation of fluid secretion suggest that leucokinins increase the Cl permeability of the tubule wall thereby increasing the availability of Cl for secretion with Na, K and water. Structure-function comparisons of the seven leucokinins studied suggest that the active region of the octapeptide is segregated to the C-terminal pentapeptide. In view of the known effects of leucokinins on hindgut motility in the cockroach, our finding of effects in mosquito Malpighian tubules suggests that leucokinins may be widely distributed in insects where they may have diverse functions in a variety of organs.