Tetanus-induced asynchronous GABA release in cultured hippocampal neurons

Brain Res. 2000 Oct 13;880(1-2):198-201. doi: 10.1016/s0006-8993(00)02746-3.

Abstract

Asynchronous GABA release was studied in cultured hippocampal neurons using paired whole-cell recordings. Tetanization of the presynaptic GABAergic neuron was accompanied by a train of IPSCs which showed tetanic depression. Asynchronous IPSCs (asIPSCs) also developed during the train and continued for 1.85+/-0.3 s after the stimulation. The threshold frequency for evoking asIPSCs was 10 Hz, while maximal asynchronous activity was achieved at 40 Hz. Perfusion with EGTA-AM blocked asIPSCs. The elevation of [Ca(2+)](i) that accompanies presynaptic action potential firing triggers asynchronous release of GABA vesicles, thereby counteracting tetanic depression of synchronous IPSCs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2-Amino-5-phosphonovalerate / pharmacology
  • 6-Cyano-7-nitroquinoxaline-2,3-dione / pharmacology
  • Action Potentials / physiology
  • Animals
  • Calcium / physiology
  • Cells, Cultured
  • Egtazic Acid / analogs & derivatives
  • Egtazic Acid / pharmacology
  • Electric Stimulation
  • Evoked Potentials / drug effects
  • Evoked Potentials / physiology
  • Hippocampus / physiology*
  • Neurons / cytology
  • Neurons / drug effects
  • Neurons / physiology*
  • Rats
  • Synapses / drug effects
  • Synapses / physiology*
  • gamma-Aminobutyric Acid / metabolism*

Substances

  • Egtazic Acid
  • gamma-Aminobutyric Acid
  • 6-Cyano-7-nitroquinoxaline-2,3-dione
  • 2-Amino-5-phosphonovalerate
  • EGTA acetoxymethyl ester
  • Calcium