title: Influence of cations on the electrical activity of neuroblastoma X glioma hybrid cells.
abstract: Electrical excitability is one of the various neuronal properties of neuroblastoma X glioma hybrid cells. At a Ca2+ concentration of 1.8 mM the action potential is inhibited by tetrodotoxin, suggesting that the inward current is carried by Na+ ions. In contrast, at a Ca2+ concentration of 20-36 mM and even in the absence of Na+, spikes (sometimes repetitive) with strong hyperpolarizing afterpotential occur, which are no longer affected by tetrodotoxin. They are, however, blocked by antagonists of Ca2+ like La3+, Co2+, Mn2+, and the synthetic compounds D-600 and BAY a-1040. This seems to indicate that at high concentrations of Ca2+, the inward current of the action potential is essentially carried by Ca2+. Sr2+, but not Mg2+ can effectively substitute for Ca2+. It slows down the time course of the action potential. Ba2+ depolarizes the membrane gradually. If Ca2+ is also present, Ba2+ causes a reduced depolarization and spontaneous action potentials with no hyperpolarizing after-potential are observed.
mesh_terms: D000200:Action Potentials / Q000187:drug effects*; D001464:Barium / Q000494:pharmacology; D002118:Calcium / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D002460:Cell Line; D002478:Cells, Cultured; D005910:Glioma / Q000473:pathology; D006801:Humans; D006822:Hybrid Cells; D008274:Magnesium / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D009447:Neuroblastoma / Q000473:pathology; D013324:Strontium / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D001464:Barium; D013779:Tetrodotoxin; D008274:Magnesium; D002118:Calcium; D013324:Strontium