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.

Abstract

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

Substances

  • Anesthetics
  • Potassium Channels
  • QX-314
  • Lidocaine