Pharmacological and electrophysiological characterization of lithium ion flux through the action potential sodium channel in neuroblastoma X glioma hybrid cells.
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.
D000109:Acetylcholine / Q000494:pharmacology; D000157:Aconitine / Q000494:pharmacology; D000200:Action Potentials; D000818:Animals; D002999:Clone Cells; D005910:Glioma; D006822:Hybrid Cells / Q000187:drug effects / Q000502:physiology*; D007473:Ion Channels / Q000378:metabolism*; D008094:Lithium / Q000378:metabolism*; D009447:Neuroblastoma; D012604:Scorpion Venoms / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism*; D013779:Tetrodotoxin / Q000494:pharmacology; D014701:Veratridine / Q000494:pharmacology
D007473:Ion Channels; D012604:Scorpion Venoms; D013779:Tetrodotoxin; D014701:Veratridine; D008094:Lithium; D012964:Sodium; D000109:Acetylcholine; D000157:Aconitine