The slow inhibitory postsynaptic potential in rat hippocampal CA1 neurones is blocked by intracellular injection of QX-314

Neurosci Lett. 1990 Mar 14;110(3):309-13. doi: 10.1016/0304-3940(90)90865-7.


Intracellular recordings were made from CA1 pyramidal neurones in the rat hippocampus slice preparation. The recording electrodes contained potassium acetate (4 M) with or without the quaternary lidocaine derivative, QX-314 (50 mM). Both fast (f) and slow (s) inhibitory postsynaptic potentials (IPSP) were evoked by low-frequency orthodromic stimulation. The s-IPSP was rapidly reduced by QX-314 injection. It decreased along a similar time course to the dV/dt of the action potential (AP). The f-IPSP and excitatory postsynaptic potential were not significantly reduced in size at a time when the s-IPSP was virtually abolished by QX-314. It is concluded that conductance through the K+ channels which are coupled to GABAB receptors is readily blocked by QX-314, while the Cl- channels which are coupled to GABAA receptors and the cation channels coupled to the glutamate receptors are relatively resistant to the local anaesthetic.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials / drug effects
  • Anesthetics / pharmacology*
  • Animals
  • Electric Stimulation
  • Hippocampus / drug effects
  • Hippocampus / physiology*
  • In Vitro Techniques
  • Lidocaine / analogs & derivatives*
  • Lidocaine / pharmacology
  • Neural Inhibition / drug effects*
  • Potassium Channels / drug effects
  • Potassium Channels / physiology*
  • Rats
  • Rats, Inbred Strains


  • Anesthetics
  • Potassium Channels
  • QX-314
  • Lidocaine