Ionic currents in PC12 cells differentiated into neuron-like cells by a cultured-sciatic nerve conditioned medium

Abstract

The present work deals with the identification of the ionic currents found in PC12 cells differentiated into neuron-like cells by a 9–11-day cultured-sciatic nerve conditioned medium (CM). PC12 whole-cell currents were measured after chronic exposure to CM. The results obtained in these CM-treated cells reveal that the functional expression of Ca 2+ currents is increased, that Na + currents are not affected, and that a transient K + current and a K + delayed rectifier (K +dr) current are increased. The combination of nifedipine and ω-conotoxin GVIA (ω-CgTX) does not block completely the increased functional expression of the Ca 2+ current. The remaining current is blocked by ω-agatoxin TK indicating that P/Q-type channels are additionally contributing to the increase in Ca 2+ current. NGF-treated PC12 cells, used as positive controls, confirm that NGF increases the expression of voltage-dependent Na + currents and of Ca 2+ currents. In addition, we found that NGF also increases a K +dr-type current in these cells. The results obtained with the CM might be due to a molecule or a mixture of molecules released into the medium by the 9–11-day cultured sciatic nerves.