Modulation of tyramine signaling by osmolality in an insect secretory epithelium
Modulation of tyramine signaling by osmolality in an insect secretory epithelium
复制标题
DOI：
10.1152/ajpcell.00026.2005
复制
发表时间：
2005-11-01
影响因子：
5.5
通讯作者：
Blumenthal, EM
中科院分区：
文献类型：
--
作者：
Blumenthal, EM
渗透压对昆虫分泌上皮酪胺信号的调节。美国生理学杂志细胞生理学289：C1261 - C1267，2005年。首次发表于2005年6月29日; doi：10.1152/ ajpcell。00026.2005. - 多细胞生物体内水平衡的控制依赖于上皮细胞的吸收和分泌过程。本研究关注渗透压对昆虫排泄系统的主要组成部分马氏管（MTs）功能的影响。先前的研究表明，生物胺酪胺增加果蝇MT的跨上皮氯离子电导和尿液分泌。这项研究表明，MT对酪胺的反应，通过跨上皮电位（TEP）的去极化测量，是由周围介质的渗透压调制。渗透压摩尔浓度的增加导致酪胺敏感性降低，而渗透压摩尔浓度的降低导致酪胺敏感性增加;渗透压摩尔浓度+/- 20%的变化导致对10 nM酪胺的响应几乎10倍调节。另一种利尿剂白细胞激肽的活性对渗透压也同样敏感，这表明调节发生在酪胺受体的下游。作为对连续酪胺信号传导的响应，如可能在体内发生的，TEP振荡，并且渗透压的增加延长了这些振荡的周期。渗透压摩尔浓度的增加也引起尿生成率的降低;这种降低被酪胺能拮抗剂育亨宾减弱。提出了一种模型，其中酪胺信号的这种调制增强了脱水应激过程中的身体水分的保护。配体信号转导的调节是渗透压的一种新效应，并且可能是上皮细胞对其环境变化做出反应的一种普遍机制。
Modulation of tyramine signaling by osmolality in an insect secretory epithelium. Am J Physiol Cell Physiol 289: C1261 - C1267, 2005. First published June 29, 2005; doi: 10.1152/ ajpcell. 00026.2005. - The control of water balance in multicellular organisms depends on absorptive and secretory processes across epithelia. This study concerns the effects of osmolality on the function of the Malpighian tubules ( MTs), a major component of the insect excretory system. Previous work has shown that the biogenic amine tyramine increases transepithelial chloride conductance and urine secretion in Drosophila MTs. This study demonstrates that the response of MTs to tyramine, as measured by the depolarization of the transepithelial potential ( TEP), is modulated by the osmolality of the surrounding medium. An increase in osmolality caused decreased tyramine sensitivity, whereas a decrease in osmolality resulted in increased tyramine sensitivity; changes in osmolality of +/- 20% resulted in a nearly 10- fold modulation of the response to 10 nM tyramine. The activity of another diuretic agent, leucokinin, was similarly sensitive to osmolality, suggesting that the modulation occurs downstream of the tyramine receptor. In response to continuous tyramine signaling, as likely occurs in vivo, the TEP oscillates, and an increase in osmolality lengthened the period of these oscillations. Increased osmolality also caused a decrease in the rate of urine production; this decrease was attenuated by the tyraminergic antagonist yohimbine. A model is proposed in which this modulation of tyramine signaling enhances the conservation of body water during dehydration stress. The modulation of ligand signaling is a novel effect of osmolality and may be a widespread mechanism through which epithelia respond to changes in their environment.