Luminal signal in tubuloglomerular feedback: what about potassium?
Luminal signal in tubuloglomerular feedback: what about potassium?
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肾小球反馈中的管腔信号：钾怎么样？
DOI：
10.1046/j.1523-1755.1998.06739.x
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
Thomson,S
中科院分区：
文献类型：
--
作者：
Vallon,V;Osswald,H;Blantz,RC;Thomson,S
肾小管-肾小球反馈中的管腔信号：钾离子如何？有证据表明，需要最小的管腔[K+]才能引起完整的肾小管肾小球反馈（TGF）反应，这与TGF信号通过Na+-2Cl--K+协同转运蛋白穿过致密斑（MD）的传递一致。此外，似乎MD处的管腔[K+]接近Na+-2Cl--K+协同转运蛋白的K+亲和力，并且响应于改变晚期近端肾小管流速（VLP）而改变，即，诱导TGF应答的操作。这些结果表明，管腔[K+]（除[Cl-]外）可能是TGF的速率限制。在亨利氏袢（TALH）的粗升支中，大部分腔中的K+来自跨顶小管膜的再循环。由于改变VLP引起的绝对Na+和Cl-输送到Henle袢的变化比K+负荷的变化大，因此尽管Na+和Cl-通过Na+-2Cl--K+共转运蛋白的K+依赖性重吸收发生了显著变化，但MD处VLP和管腔[K+]的平行变化意味着TALH中K+再循环的转运依赖性适应。
Luminal signal in tubuloglomerular feedback: What about potassium?Evidence suggests that a minimal luminal [K+] is required to elicit a full tubuloglomerular feedback (TGF) response, consistent with transmission of the TGF signal across the macula densa (MD) via the Na+-2Cl--K+cotransporter. Furthermore, it appears that luminal [K+] at the MD is close to the K+affinity of the Na+-2Cl--K+cotransporter and changes in response to altering late proximal tubular flow rate (VLP), that is, a maneuver that induces a TGF response. These findings suggest that luminal [K+] (besides [Cl-]) could be rate limiting in TGF. In the thick ascending limb of Henle's loop (TALH), most of the luminal K+is derived from recycling across the apical tubular membrane. Because changing VLP causes relatively greater alterations in the absolute Na+and Cl-delivery to Henle's loop than in K+load, the parallel changes of VLP and luminal [K+] at the MD, despite significant alteration in K+-dependent reabsorption of Na+and Cl-via the Na+-2Cl--K+cotransporter, imply a transport-dependent adaptation of K+recycling in TALH.