Sodium dynamics underlying burst firing and putative mechanisms for the regulation of the firing pattern in midbrain dopamine neurons: a computational approach

J Comput Neurosci. 1999 Jan;6(1):49-69. doi: 10.1023/a:1008809000182.

Abstract

A physiologically based multicompartmental computational model of a midbrain dopamine (DA) neuron, calibrated using data from the literature, was developed and used to test the hypothesis that sodium dynamics drive the generation of a slow oscillation postulated to underlie NMDA-evoked bursting activity in a slice preparation. The full compartmental model was reduced to three compartments and ultimately to two variables, while retaining the biophysical interpretation of all parameters. A phase-plane analysis then suggested two mechanisms for the regulation of the firing pattern: (1) bursting activity is favored by manipulations that enhance the region of negative slope in the whole-cell IV curve and inhibited by those manipulations, such as increasing linear currents, that tend to dampen this region and (2) assuming a region of negative slope is present in the IV curve, the bias of the system can be altered, either enabling or disabling bursting. The model provides a coherent framework for interpreting the effects of glutamate, aspartate, NMDA, and GABA agonists and antagonists under current-clamp conditions, as well as the effects of NMDA and barium under voltage-clamp conditions.

Publication types

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

MeSH terms

  • Calibration
  • Computer Simulation*
  • Dopamine / physiology*
  • In Vitro Techniques
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology
  • Mesencephalon / cytology
  • Mesencephalon / drug effects
  • Mesencephalon / physiology*
  • Models, Neurological*
  • N-Methylaspartate / physiology
  • Neurons / drug effects
  • Neurons / physiology*
  • Oscillometry
  • Patch-Clamp Techniques
  • Sodium / metabolism*

Substances

  • N-Methylaspartate
  • Sodium
  • Dopamine