Intracellular QX-314 inhibits calcium currents in hippocampal CA1 pyramidal neurons

J Neurophysiol. 1996 Sep;76(3):2120-4. doi: 10.1152/jn.1996.76.3.2120.


1. The effects of intracellular QX-314 on Ca2+ currents were examined in CA1 pyramidal cells acutely isolated from rat hippocampus. In neurons dialyzed with 10 mM QX-314 (bromide salt), the amplitude of the high-threshold Ca2+ current was on average 20% of that in control cells and the current-voltage relationships (I-Vs) were shifted in the positive voltage direction. 2. The positive shift in the I-Vs was due to the presence of intracellular Br-, because it was reproduced by 10 mM NaBr and was not present when the chloride salt of QX-314 was used. 3. Low-threshold (T-type) Ca2+ currents, at test voltages of -50 and -40 mV, were on average < 45% of control amplitude in cells containing 10 mM QX-314 (chloride salt) and < 10% of control amplitude in cells with 10 mM QX-314 (bromide salt). 4. In neurons dialyzed with 1 mM QX-314, high-threshold Ca2+ currents were still significantly different from control and Na+ currents were not completely blocked. 5. The proportions of high-threshold Ca2+ current blocked by omega-conotoxin GVIA, omega-agatoxin IVA, and nimodipine were similar in cells dialyzed with 10 mM QX-314 and control cells, indicating that the drug does not selectively inhibit any of the Ca2+ channel subtypes distinguished by these antagonists.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anesthetics, Local / pharmacology*
  • Animals
  • Calcium Channel Blockers / pharmacology*
  • Hippocampus / cytology
  • Hippocampus / drug effects
  • Hippocampus / physiology*
  • Lidocaine / analogs & derivatives*
  • Lidocaine / pharmacology
  • Membrane Potentials / physiology
  • Models, Neurological
  • Pyramidal Cells / drug effects
  • Pyramidal Cells / metabolism*
  • Rats
  • Sodium Channels / drug effects
  • Sodium Channels / metabolism


  • Anesthetics, Local
  • Calcium Channel Blockers
  • Sodium Channels
  • QX-314
  • Lidocaine