Membrane current responses to intracellular injections of inositol 1,3,4,5-tetrakisphosphate and inositol 1,3,4-trisphosphate in NG108-15 hybrid cells.
Iontophoretic injections of inositol 1,4,5-trisphosphate inside neuroblastoma X glioma NG108-15 hybrid cells evoked an outward K+ current across the outer cell membrane, probably activated by the release of intracellular Ca2+. No such current was produced by equivalent intracellular injections of inositol 1,3,4-trisphosphate or inositol 1,3,4,5-tetrakisphosphate. Instead, these compounds evoked an inward current with a reversal potential of about -20 mV, and which may therefore be due to a non-specific cation conductance. This suggests that these derivatives are unable to release sufficient Ca2+ to activate the Ca2+-dependent K+ current in these cells.
D000818:Animals; D002118:Calcium / Q000502:physiology*; D002460:Cell Line; D002462:Cell Membrane / Q000502:physiology; D004553:Electric Conductivity; D005910:Glioma; D007295:Inositol Phosphates / Q000494:pharmacology*; D007473:Ion Channels / Q000502:physiology*; D007478:Iontophoresis; D009447:Neuroblastoma; D009474:Neurons / Q000502:physiology*; D011188:Potassium / Q000502:physiology; D013403:Sugar Phosphates / Q000494:pharmacology*
D007295:Inositol Phosphates; D007473:Ion Channels; D013403:Sugar Phosphates; D011188:Potassium; D002118:Calcium