Changes in levels of D1, D2, or NMDA receptors during withdrawal from brief or extended daily access to IV cocaine

Brain Res. 2007 Feb 2;1131(1):220-8. doi: 10.1016/j.brainres.2006.10.069. Epub 2006 Dec 11.

Abstract

We previously reported that brief (1 h), but not extended (6 h), daily access to cocaine results in a sensitized locomotor response to cocaine and in elevated c-Fos immunoreactivity and DAT binding in the nucleus accumbens (N.Acc) core. In order to better our understanding of the neural adaptations mediating the transition from controlled drug use to addiction, the current experiments were set to further explore the neural adaptations resulting from these two access conditions. Rats received either brief daily access to saline or cocaine, or brief daily access followed by extended daily access to cocaine. Subjects were then sacrificed either 20 min, or 14 or 60 days, after the last self-administration session. Samples of the ventral tegmental area (VTA), N.Acc core and shell, dorsal striatum, and medial prefrontal cortex (mPFC) were taken for analysis of D1 ([3H]SCH-23390), D2 ([3H]Spiperone), and NMDA ([3H]MK-801) receptor binding (using the method of receptor autoradiography). At 20 min into withdrawal, D2 receptors were elevated and NMDA receptors were reduced in the mPFC of the brief access animals while D1 receptors were elevated in the N.Acc shell of the extended access animals, compared to saline controls. D2 receptors were reduced in the N.Acc shell of the brief access animals compared to saline controls after 14 days, and compared to extended access animals after 60 days of withdrawal. In summary, extended access to cocaine resulted in only transient changes in D1 receptors binding. These results suggest that the development of compulsive drug use is largely unrelated to changes in total binding of D2 or NMDA receptors.

Publication types

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

MeSH terms

  • Adaptation, Physiological / drug effects
  • Adaptation, Physiological / physiology
  • Animals
  • Binding, Competitive / drug effects
  • Binding, Competitive / physiology
  • Brain Chemistry / drug effects*
  • Brain Chemistry / physiology
  • Cocaine / adverse effects*
  • Cocaine-Related Disorders / metabolism*
  • Cocaine-Related Disorders / physiopathology
  • Disease Models, Animal
  • Dopamine / metabolism
  • Dopamine Uptake Inhibitors / adverse effects
  • Drug Administration Schedule
  • Glutamic Acid / metabolism
  • Injections, Intravenous
  • Male
  • Neural Pathways / drug effects
  • Neural Pathways / metabolism
  • Neural Pathways / physiopathology
  • Nucleus Accumbens / drug effects
  • Nucleus Accumbens / metabolism
  • Nucleus Accumbens / physiopathology
  • Radioligand Assay
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Dopamine / drug effects*
  • Receptors, Dopamine / metabolism
  • Receptors, Dopamine D1 / drug effects
  • Receptors, Dopamine D1 / metabolism
  • Receptors, Dopamine D2 / drug effects
  • Receptors, Dopamine D2 / metabolism
  • Receptors, N-Methyl-D-Aspartate / drug effects*
  • Receptors, N-Methyl-D-Aspartate / metabolism
  • Substance Withdrawal Syndrome / metabolism*
  • Substance Withdrawal Syndrome / physiopathology
  • Synaptic Transmission / drug effects
  • Synaptic Transmission / physiology

Substances

  • Dopamine Uptake Inhibitors
  • Receptors, Dopamine
  • Receptors, Dopamine D1
  • Receptors, Dopamine D2
  • Receptors, N-Methyl-D-Aspartate
  • Glutamic Acid
  • Cocaine
  • Dopamine