State-dependent bidirectional modification of somatic inhibition in neocortical pyramidal cells

Neuron. 2008 Mar 27;57(6):905-16. doi: 10.1016/j.neuron.2008.01.030.

Abstract

Cortical pyramidal neurons alter their responses to input signals depending on behavioral state. We investigated whether changes in somatic inhibition contribute to these alterations. In layer 5 pyramidal neurons of rat visual cortex, repetitive firing from a depolarized membrane potential, which typically occurs during arousal, produced long-lasting depression of somatic inhibition. In contrast, slow membrane oscillations with firing in the depolarized phase, which typically occurs during slow-wave sleep, produced long-lasting potentiation. The depression is mediated by L-type Ca2+ channels and GABA(A) receptor endocytosis, whereas potentiation is mediated by R-type Ca2+ channels and receptor exocytosis. It is likely that the direction of modification is mainly dependent on the ratio of R- and L-type Ca2+ channel activation. Furthermore, somatic inhibition was stronger in slices prepared from rats during slow-wave sleep than arousal. This bidirectional modification of somatic inhibition may alter pyramidal neuron responsiveness in accordance with behavioral state.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2-Amino-5-phosphonovalerate / pharmacology
  • Action Potentials / drug effects
  • Action Potentials / physiology
  • Action Potentials / radiation effects
  • Animals
  • Animals, Newborn
  • Bicuculline / analogs & derivatives
  • Bicuculline / pharmacology
  • Dendrites / drug effects
  • Dendrites / physiology*
  • Dose-Response Relationship, Drug
  • Dose-Response Relationship, Radiation
  • Electric Stimulation / methods
  • Excitatory Amino Acid Antagonists / pharmacology
  • GABA Antagonists / pharmacology
  • Inhibitory Postsynaptic Potentials / drug effects
  • Inhibitory Postsynaptic Potentials / physiology
  • Inhibitory Postsynaptic Potentials / radiation effects
  • Neural Inhibition / physiology*
  • Patch-Clamp Techniques / methods
  • Pyramidal Cells / cytology*
  • Quinoxalines / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Spider Venoms / pharmacology
  • Visual Cortex / cytology*
  • gamma-Aminobutyric Acid / pharmacology

Substances

  • Excitatory Amino Acid Antagonists
  • GABA Antagonists
  • Quinoxalines
  • SNX 482
  • Spider Venoms
  • bicuculline methiodide
  • gamma-Aminobutyric Acid
  • FG 9041
  • 2-Amino-5-phosphonovalerate
  • Bicuculline