O-2-SENSITIVE K-TREATED PC12 CELL VARIANTS( CURRENT IN UNDIFFERENTIATED AND NGF)

It has been reported that cultured PC12 cells can be used as a model f or studying mechanisms of O-2 sensitivity, previously examined in peri pheral chemoreceptors and some neurons. This study compared the hypoxi c depression of K+ currents in two PC12 variants, before and after dif ferentiation into neurone-like cells induced by nerve growth factor (N GF). The results show that interaction of O-2, and K+ channels is stro ngly-voltage dependent in the PC12/TM but not the PC12/ES subline. In PC12/TM cells an effect of hypoxia on the K+ current was appreciable o nly at moderately depolarized voltages, with a loss of sensitivity at +40 to +50 mV. NGF-induced transformation did not affect the responses seen in undifferentiated cells. These results emphasize the importanc e of screening PC12 cells before selecting a variant for studying O-2 sensitivity. In view of evidence cited in the literature that hypoxia may effect membrane channels directly, further molecular and biophysic al studies of the differences among PC12 variants are required.