Signaling by intracellular Ca2+ and H+ in larval mosquito (Aedes aegypti) midgut epithelium in response to serosal serotonin and lumen pH.
Signaling by intracellular Ca2+ and H+ in larval mosquito (Aedes aegypti) midgut epithelium in response to serosal serotonin and lumen pH.
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幼虫蚊子（埃及伊蚊）中肠上皮细胞内 Ca2 和 H 信号对浆膜血清素和管腔 pH 值的反应。
DOI：
10.1016/j.jinsphys.2011.11.019
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发表时间：
2012
影响因子：
2.2
通讯作者：
Goss,GregG
中科院分区：
文献类型：
--
作者：
Moffett,DavidF;Jagadeshwaran,Urmila;Wang,Zeping;Davis,HanaM;Onken,Horst;Goss,GregG
中肠的幼虫蚊子（埃及伊蚊）介导的一个周期的碱分泌在前段（AMG），然后在后段（PMG）的部分reacidification;这两个过程都是依赖于降钙素。在这里，我们报告说，细胞内Ca 2+（Cai 2+）所示的Fura-2荧光，是升高的两个组织中的血清素的反应，但不同的时间过程中的两个肠段的特点，和Ca 2 +-免费的解决方案废除了AMG中的血清素的反应，但不是在PMG，而毒胡萝卜素，内质网Ca 2+转运的抑制剂，废除响应5-HT在PMG。这些结果表明，Ca 2+信号的起源不同的两种组织之间。实时定量RT-PCR显示AMG中5种推定的5-HT受体类型的表达，包括预期启动Ca 2+信号的5-HT 2样受体。这些受体在PMG中均不高表达。环磷酸腺苷（cAMP）是两种组织的促分泌素，但H89，蛋白激酶A（PKA）的抑制剂，也是一种促分泌素，这表明cAMP的刺激作用涉及非PKA途径。细胞松弛素B和D阻断了AMG中5-HT的作用，表明该组织中基础V-ATP酶激活的囊泡融合机制。最后，在PMG中，如通过BCECF荧光测量的，管腔pH升高增加（Cai 2+）并降低细胞内pH。这些反应表明PMG的酸分泌速率可能对局部管腔再酸化的需求以及血清羟色胺有反应。
The midgut of larval mosquitoes (Aedes aegypti) mediates a cycle of alkali secretion in the anterior segment (AMG) followed by partial reacidification in the posterior segment (PMG); both processes are serotonin-dependent. Here we report that intracellular Ca2+(Cai2+) as indicated by Fura-2 fluorescence, is elevated in both tissues in response to serotonin, but the time courses differ characteristically in the two gut segments, and Ca2+-free solution abolishes the serotonin response in AMG, but not in PMG, whereas Thapsigargin, an inhibitor of endoplasmic Ca2+transport, abolished responsiveness to 5-HT in PMG. These results suggest the origins for the Ca2+signal differ between the two tissues. Quantitative real-time RT-PCR revealed expression of 5 putative 5-HT receptor types in AMG, including 5-HT2-like receptors which would be expected to initiate a Ca2+signal. None of these receptors were highly expressed in PMG. Cyclic AMP (cAMP) is a secretagogue for both tissues, but H89, an inhibitor of Protein Kinase A (PKA), is also a secretagogue, suggesting that the stimulatory effect of cAMP involves a non-PKA pathway. Cytochalasins B and D block the effect of 5-HT in AMG, suggesting a vesicle-fusion mechanism of activation of the basal V-ATPase in this tissue. Finally, in PMG, elevation of luminal pH increases (Cai2+) and decreases intracellular pH as measured by BCECF fluorescence. These responses suggest that the rate of acid secretion by PMG might be responsive to local demand for luminal reacidification as well as to serosal serotonin.