Classification Of Potassium And Chlorine Ionic Currents In Retinal Ganglion Cell Line (RGC-5) And Effects Of Aluminum On Some Ionic Currents Of RGC-5and PC12Cell

Retinal ganglion cell line (RGC-5) has been widely used as a valuable model for studying pathophysiology and physiology of retinal ganglion cells (RGCs) in-vitro. However, the electrophysiological characteristics especially thorough classification of ionic currents in the cell line remains to be elucidated in detail. In the present paper, we determined the resting membrane potential in RGC-5cell line, and then identified different types of ionic currents by using the whole cell patch-clamp technique. The resting membrane potential (RMP) recorded in the cell line was between-30and-6mV (-17.6±2.6mV, n=10). We recorded the following voltage-gated ion channel currents:(1) inwardly rectifying Cl" current (ICl,ir), which could be blocked by Zn2+;(2) Ca2+-activated Cl-current (ICl,ca), which was sensitive to extracellular Ca2+and could be inhibited by disodium4,4’-diisothio-cyanatostilbene-2,2’-disulfonate (DIDS);(3) Inwardly rectifying K+currents (IK1), which could be blocked by Ba2+;(4) a small amount of delayed rectifier K+current (Ik). On the other hand, the voltage-gated sodium channels current (INa) and transient outward potassium channels current (IA) were not observed in this cell line. These results further characterize the ionic currents in the RGC-5cell line and might benefit further studies especially in (patho)physiology and selection of chemical medicine in in-vitro applying of certain ion channels of the RGC-5cell line.Aluminum is the most widely distributed metal in the environment and is extensively used in modern daily life. However, it is not indispensable to animals and humans. The neurotoxicity of aluminum is related to lots of neurodegenerative disease in clinical research in the past few decades (Alzheimer’s disease, Parkinson’s disease and Dialysis enlephalopathy). In this study, with the different gradient concentration and different gradient time, we investigate the effect of aluminum chloride on the ionic channel currents of RGC-5and PC12by using the whole cell patch-clamp technique. The results showed that:(1)0.1mM AICl3could superessed the Ca2+-activated Cl" current (/ci,ca) significantly in RGC-5;(2) The peak amplititudes of IK and IA were inhibited inordinately in RGC-5after application0.2mM AICl3, and the effectiveness of IA was still further notable. Beyond that, the peak amplititudes of IK and IA were decreased further and IA was disappeared almost. The results suggested that Al3+could suppress some votaged-gated K+currents and Ca2+-activated Cl-current, which might contribute to the mechanism of aluminum correlating with the development of some neurodegenerative disease.