The Role of Swelling-Activated Chloride Currents (ICL,swell) in the Regulatory Volume Decrease Response of Freshly Dissociated Rat Articular Chondrocytes

Cellular Physiology and Biochemistry

关键词: Articular chondrocytes;    Hyposmotic challenge;    Regulatory volume decrease;    Swelling activated chloride currents;    Patch clamp;   

DOI  :  10.1159/000343316

学科分类：分子生物学，细胞生物学和基因

来源: S Karger AG

【 摘 要 】

Background/Aims Articular chondrocytes dwell in an environment that is continuously changing its osmolarity as a consequence of mechanical loading, yet their volume regulation capabilities (RVD) are not fully understood. This work aimed to determine the osmotic sensitivity of freshly isolated rat chondrocytes, their RVD capabilities and to study the properties of any anion currents associated. Methods Cell volume responses were determined by microscopy. Whole cell patch clamp was used to record ion currents. Results Chondrocytes showed to be osmotically sensitive and capable of RVD in a size-dependent manner. RVD was accompanied by activation of outwardly rectifying chloride currents, featuring time and voltage independent activation and inactivation at most depolarizing voltage levels, with an anion selectivity sequence of SCN->I-≅NO3->Br->Cl->F->> Gluconate-> Methanesulphonate-, corresponding to Eisenman’s sequence I. They were also permeable to taurine. These currents were blocked by DIDS, SITS, 9-AC and NPPB and by drugs that block ICl,swell such as fluoxetine, phloretin, DCPIB and tamoxifen. RT-PCR assays show the presence of mRNA for CLC-3 and TMEM16A, that had been proposed as molecular determinants of ICl,swell currents. Conclusions These findings indicate that freshly isolated rat articular chondrocytes have ICl,swell. The further finding that ICl,swell blockers alter the RVD response suggest that ICl,swell is involved in the RVD response of rat articular chondrocytes.

【 授权许可】

CC BY-NC-ND