Pharmacological and Electrophysiological Characterization of Lithium Ion Flux Through the Action Potential Sodium Channel in Neuroblastoma × Glioma Hybrid Cells |
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Authors: | G Reiser F Scholz B Hamprecht |
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Institution: | Physiologisch-chemisches Institut der Universität Würzburg, Würzburg, F.R.G. |
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Abstract: | Interaction of Li+ with the voltage-dependent Na+ channel has been analyzed in neuroblastoma X glioma hybrid cells. The cells were able to generate action potentials in media containing Li+ instead of Na+. The uptake of Li+ into the hybrid cells was investigated for the pharmacological analysis of Li+ permeation through voltage-dependent Na+ channels. Veratridine and aconitine increased the uptake of Li+ to the same degree (EC50 30 microM). This increase was blocked by tetrodotoxin (IC50 20 nM). Veratridine and aconitine did not act synergistically; however, the veratridine-stimulated influx was further enhanced by the toxin of the scorpion Leiurus quinquestriatus (EC50 0.06 micrograms/ml). This stimulation was also blocked by tetrodotoxin. Thus, the voltage-dependent Na+ channel of the hybrid cells accepts both Li+ and Na+ in a similar manner. |
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Keywords: | Li+ flux Voltage-dependent Na+ channel Neurotoxins Neuroblastoma × glioma hybrid cells |
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