Cocaine self-administration leads to alterations in temporal responses to cocaine challenge in limbic and motor circuitry

Eur J Neurosci. 2011 Sep;34(5):800-15. doi: 10.1111/j.1460-9568.2011.07806.x.

Abstract

Chronic use of cocaine is associated with lasting alterations in brain metabolism, circuitry, and receptor properties. We used neuroimaging with pharmacological magnetic resonance imaging to assess alterations in response to cocaine (0.5 mg/kg) in animals trained to self-administer cocaine on a fixed-ratio 5 schedule of reinforcement, as well as saline-yoked controls, after 28 days of cocaine abstinence. We fitted the cerebral blood volume (CBV) curves for full-width half-maximum (FWHM) as well as peak CBV response. There were significant increases in the FWHM of the response curves in the cocaine self-administering (SA) animals as compared with saline-yoked controls in the medial prefrontal cortex (mPFC) and the caudate/putamen (CPu), and increases in peak CBV in the M1 motor cortex, CPu, and pedunculopontine tegmental nucleus. Functional connectivity analysis showed increased correlations in the cocaine SA rats upon acute cocaine challenge, especially in the S1, mPFC, and thalamus. As D3 receptor expression is postulated to increase following chronic cocaine administration, we also examined the response to 0.2 mg/kg of the D3-preferring agonist 7-hydroxy-N,N-di-n-propyl-2-aminotetralin (7-OHDPAT). Cocaine SA animals showed a decreased overall CBV response to this drug, except in the globus pallidus. The hypothalamus showed a negative CBV change in response to cocaine challenge, similar to that noted with the D3 agonist, and showed a smaller response in the cocaine SA animals than in the controls. Given the good coupling of cerebral hemodynamics with dopamine dynamics previously observed with pharmacological magnetic resonance imaging, these data suggest that increased persistence of dopamine in the prefrontal cortex may be responsible for some of the behavioral alterations observed subsequent to chronic cocaine use.

Publication types

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

MeSH terms

  • Animals
  • Brain / anatomy & histology*
  • Brain / drug effects*
  • Brain / physiology
  • Cerebrovascular Circulation / drug effects
  • Cocaine / administration & dosage*
  • Cocaine / pharmacology*
  • Dopamine Agonists / pharmacology
  • Dopamine Uptake Inhibitors / administration & dosage
  • Dopamine Uptake Inhibitors / pharmacology
  • Humans
  • Limbic System / anatomy & histology*
  • Limbic System / drug effects*
  • Limbic System / physiology
  • Magnetic Resonance Imaging
  • Male
  • Neural Pathways / anatomy & histology
  • Neural Pathways / drug effects*
  • Neural Pathways / physiology
  • Rats
  • Rats, Sprague-Dawley
  • Regional Blood Flow / drug effects
  • Reinforcement, Psychology
  • Self Administration
  • Tetrahydronaphthalenes / pharmacology

Substances

  • Dopamine Agonists
  • Dopamine Uptake Inhibitors
  • Tetrahydronaphthalenes
  • Cocaine
  • 7-hydroxy-2-N,N-dipropylaminotetralin