Huang S J, Fu W O, Chung Y W, Zhou T S, Wong P Y
Department of Physiology, Faculty of Medicine, Chinese University of Hong Kong, Shatin, NT.
Am J Physiol. 1993 Apr;264(4 Pt 1):C794-802. doi: 10.1152/ajpcell.1993.264.4.C794.
Single rat epididymal cell studied under whole cell patch-clamp condition responded to 8-(4-chlorophenylthio)-adenosine 3',5'-cyclic monophosphate (CPT-cAMP) (500 microM) and to ionomycin (1 microM) by an increase in whole cell conductance. A major part of the stimulated current was carried by Cl-, although a small part was due to nonselective cation current. After elimination of the cation current component by using impermeant cation, the cells revealed different Cl- conductance properties in response to adenosine 3',5'-cyclic monophosphate (cAMP) and ionomycin. The cAMP-stimulated Cl- conductance was independent of time and voltage and showed a linear current-voltage relationship. The anion permselectivity was NO3- > Br- > Cl- approximately I- >> SO(4)2-. The ionomycin-stimulated Cl- conductance showed marked time and voltage dependency. In contrast to the cAMP-induced anion permselectivity, the ionomycin-induced anion permselectivity was I- > Br- approximately NO3- > Cl- >> SO(4)2-. These results indicate that the epididymal epithelial cells exhibit different Cl- conductances sensitive to cAMP and Ca2+. The cAMP-activated conductance has properties resembling the type associated with the cystic fibrosis transmembrane conductance regulator found in cystic fibrosis-affected epithelia. This finding supports the notion that the epididymis is a cystic fibrosis epithelium.
在全细胞贴片钳条件下研究的单个大鼠附睾细胞对8 -（4 - 氯苯硫基）-腺苷3'，5'-环磷酸（CPT - cAMP）（500 microM）和离子霉素（1 microM）的反应是全细胞电导增加。刺激电流的主要部分由Cl-携带，尽管一小部分是由于非选择性阳离子电流。在用非渗透性阳离子消除阳离子电流成分后，细胞对腺苷3'，5'-环磷酸（cAMP）和离子霉素表现出不同的Cl-电导特性。cAMP刺激的Cl-电导与时间和电压无关，呈现线性电流-电压关系。阴离子选择通透性为NO3- > Br- > Cl- ≈ I- >> SO(4)2-。离子霉素刺激的Cl-电导表现出明显的时间和电压依赖性。与cAMP诱导的阴离子选择通透性相反，离子霉素诱导的阴离子选择通透性为I- > Br- ≈ NO3- > Cl- >> SO(4)2-。这些结果表明附睾上皮细胞表现出对cAMP和Ca2+敏感的不同Cl-电导。cAMP激活的电导具有类似于在受囊性纤维化影响的上皮中发现的囊性纤维化跨膜电导调节因子相关类型的特性。这一发现支持了附睾是囊性纤维化上皮的观点。
