Interactions between distinct GABA(A) circuits in hippocampus

Neuron. 2000 Feb;25(2):449-57. doi: 10.1016/s0896-6273(00)80907-1.


Synchronous activity among synaptically connected interneurons is thought to organize temporal patterns such as gamma and theta rhythms in cortical circuits. Interactions between distinct interneuron circuits may underlie more complex patterns, such as nested rhythms. Here, we demonstrate such an interaction between two groups of CA1 interneurons, GABA(A,slow) and GABA(A,fast) cells, that may contribute to theta and gamma rhythms, respectively. Stratum lacunosum-moleculare (SL-M) stimuli that activate GABA(A,slow) inhibitory postsynaptic currents (IPSCs) in pyramidal cells simultaneously depress the rate and amplitude of spontaneous GABA(A,fast) IPSCs for several hundred milliseconds. This suppression has a similar pharmacological profile to GABA(A,slow) IPSCs, and SL-M stimuli elicit GABA(A,slow) IPSCs in interneurons. We conclude that GABA(A,slow) cells inhibit both pyramidal cells and GABA(A,fast) interneurons and postulate that this interaction contributes to nested theta/gamma rhythms in hippocampus.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Computer Simulation
  • Hippocampus / cytology*
  • Interneurons / chemistry
  • Interneurons / cytology*
  • Interneurons / metabolism
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology
  • Models, Neurological
  • Neural Inhibition / physiology
  • Neural Pathways / physiology
  • Neurotransmitter Uptake Inhibitors / pharmacology
  • Nipecotic Acids / pharmacology
  • Oximes / pharmacology
  • Patch-Clamp Techniques
  • Pyramidal Cells / chemistry
  • Pyramidal Cells / cytology*
  • Pyramidal Cells / metabolism
  • Rats
  • Receptors, GABA-A / physiology*
  • Theta Rhythm
  • gamma-Aminobutyric Acid / metabolism


  • Neurotransmitter Uptake Inhibitors
  • Nipecotic Acids
  • Oximes
  • Receptors, GABA-A
  • NNC 711
  • gamma-Aminobutyric Acid