Differences in biophysical properties of nucleus accumbens medium spiny neurons emerging from inactivation of inward rectifying potassium currents

J Comput Neurosci. 2009 Dec;27(3):453-70. doi: 10.1007/s10827-009-0161-7. Epub 2009 Jun 2.

Abstract

Inward rectifying potassium (K(IR)) currents in medium spiny (MS) neurons of nucleus accumbens inactivate significantly in approximately 40% of the neurons but not in the rest, which may lead to differences in input processing by these two groups. Using a 189-compartment computational model of the MS neuron, we investigate the influence of this property using injected current as well as spatiotemporally distributed synaptic inputs. Our study demonstrates that K(IR) current inactivation facilitates depolarization, firing frequency and firing onset in these neurons. These effects may be attributed to the higher input resistance of the cell as well as a more depolarized resting/down-state potential induced by the inactivation of this current. In view of the reports that dendritic intracellular calcium levels depend closely on burst strength and spike onset time, our findings suggest that inactivation of K(IR) currents may offer a means of modulating both excitability and synaptic plasticity in MS neurons.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aplysia
  • Biophysical Phenomena / physiology*
  • Biophysics / methods
  • Computer Simulation
  • Electric Stimulation / methods
  • Excitatory Amino Acid Agonists / pharmacology
  • Ion Channel Gating / drug effects
  • Ion Channel Gating / physiology
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology
  • Models, Neurological*
  • N-Methylaspartate / pharmacology
  • Neurons / classification
  • Neurons / physiology*
  • Neurons / ultrastructure
  • Nucleus Accumbens / cytology*
  • Potassium Channels, Inwardly Rectifying / physiology*
  • Reaction Time / drug effects
  • Reaction Time / physiology
  • Synapses / drug effects
  • Synapses / physiology
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / pharmacology

Substances

  • Excitatory Amino Acid Agonists
  • Potassium Channels, Inwardly Rectifying
  • N-Methylaspartate
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid