Onuchic L F, Arenstein I R, Lopes A G
Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Brasil.
Braz J Med Biol Res. 1990;23(8):739-42.
Thin ascending limb cells from Henle's loop were studied with optical and video techniques to evaluate cell volume regulation in response to anisoosmotic media and its ionic dependence. Cell volume regulation was observed when these cells were exposed to hypoosmotic solutions. Under hyperosmotic conditions only an osmometric response was found, with no volume regulatory increase (VRI). The removal of Cl- or HCO3- abolished the volume regulatory decrease (VRD) normally observed during exposure to hypoosmotic solutions. Re-addition of these ions did not elicit the VRD response. The removal of K+ from hypoosmotic solutions abolished VRD but its re-introduction restored the volume regulatory response. In the absence of Na+, a partial inhibition of VRD was found; re-addition of Na+ completely restored the regulatory response. These indicate that cells from the thin ascending limb of Henle's loop regulate their volume under hypoosmotic conditions, and that this process is dependent upon Cl-, HCO3-, Na+ and K+, with different patterns of response being observed upon addition or deletion of these ions.
利用光学和视频技术研究了髓袢升支细段细胞，以评估细胞对非等渗介质的容积调节及其离子依赖性。当这些细胞暴露于低渗溶液时，可观察到细胞容积调节。在高渗条件下，仅发现渗透反应，而无容积调节性增加（VRI）。去除Cl-或HCO3-可消除在暴露于低渗溶液期间通常观察到的容积调节性降低（VRD）。重新添加这些离子不会引发VRD反应。从低渗溶液中去除K+可消除VRD，但重新引入K+可恢复容积调节反应。在无Na+的情况下，发现VRD受到部分抑制；重新添加Na+可完全恢复调节反应。这些表明，髓袢升支细段细胞在低渗条件下调节其容积，并且该过程依赖于Cl-、HCO3-、Na+和K+，在添加或去除这些离子时观察到不同的反应模式。
