D2 dopamine modulation of corticoaccumbens synaptic responses changes during adolescence

Eur J Neurosci. 2008 Mar;27(6):1364-72. doi: 10.1111/j.1460-9568.2008.06107.x. Epub 2008 Mar 7.

Abstract

Dopaminergic afferents from the ventral tegmental area (VTA) modulate information processing in the nucleus accumbens (NA), a brain region critical for motivation and reward mechanisms. In NA medium spiny neurons (MSNs) from young rats, D(2) agonists have been shown to decrease the amplitude of corticoaccumbens synaptic responses. As several dopamine-related functions change during adolescence, we assessed the D(2) modulation of cortical inputs with whole-cell recordings in slices obtained from adult and preadolescent rats. The D(2) agonist quinpirole (5 microM) decreased synaptic response of NA MSNs to electrical cortical stimulation in slices from preadolescent rats. In slices from adult rats, however, quinpirole increased both the amplitude of evoked synaptic responses and the frequency of spontaneous synaptic events. These effects were blocked by the GABA-A antagonist picrotoxin (50 microM), revealing a D(2)-mediated decrease These results suggest that D(2) receptors modulate NA neurons differently in young and adult rats, due to the emergence of a D(2)-facilitated GABA component in corticoaccumbens responses during adolescence.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Age Factors
  • Animals
  • Cerebral Cortex / cytology
  • Cerebral Cortex / drug effects
  • Cerebral Cortex / physiology*
  • Dopamine / physiology*
  • Dopamine Agonists / pharmacology
  • Excitatory Postsynaptic Potentials / drug effects
  • Excitatory Postsynaptic Potentials / physiology
  • Male
  • Neural Pathways / cytology
  • Neural Pathways / drug effects
  • Neural Pathways / physiology
  • Nucleus Accumbens / cytology
  • Nucleus Accumbens / drug effects
  • Nucleus Accumbens / physiology*
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Dopamine D2 / agonists
  • Receptors, Dopamine D2 / physiology*
  • Synapses / drug effects
  • Synapses / physiology*
  • gamma-Aminobutyric Acid / physiology

Substances

  • Dopamine Agonists
  • Receptors, Dopamine D2
  • gamma-Aminobutyric Acid
  • Dopamine