Ionic currents in PC12 cells differentiated into neuron-like cells by a cultured-sciatic nerve conditioned medium.
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 omega-conotoxin GVIA (omega-CgTX) does not block completely the increased functional expression of the Ca(2+) current. The remaining current is blocked by omega-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.
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Centro de Biociencias y Medicina Molecular, Instituto de Estudios Avanzados (IDEA), Apartado 17606, Caracas 1015-A, Venezuela. ccastill@reacciun.ve
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D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects* / Q000502:physiology; D017077:Culture Media, Conditioned / Q000494:pharmacology*; D007473:Ion Channels / Q000187:drug effects* / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D020932:Nerve Growth Factor / Q000494:pharmacology; D009414:Nerve Growth Factors / Q000494:pharmacology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D016716:PC12 Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D012584:Sciatic Nerve / Q000378:metabolism; D015222:Sodium Channels / Q000187:drug effects / Q000378:metabolism
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D017077:Culture Media, Conditioned; D007473:Ion Channels; D009414:Nerve Growth Factors; D015221:Potassium Channels; D015222:Sodium Channels; D020932:Nerve Growth Factor