Sensitization to amphetamine, but not PCP, impairs attentional set shifting : reversal by a D1 receptor agonist injected into the medial prefrontal cortex

Repeated exposure to psychomotor stimulants can lead to sensitization to their effects, and sensitization has been implicated in the pathophysiology of schizophrenia and drug abuse. These disorders are characterized by cognitive deficits, particularly in prefrontally mediated executive function. The...

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Bibliographic Details
Published in:Psychopharmacologia 2005-12, Vol.183 (2), p.190-200
Main Authors: FLETCHER, Paul J, TENN, Catherine C, RIZOS, Zoë, LOVIC, Vedran, KAPUR, Shitij
Format: Article
Language:English
Subjects:
2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine - administration & dosage
Amphetamine - adverse effects
Analysis of Variance
Animals
Attention Deficit Disorder with Hyperactivity - chemically induced
Attention Deficit Disorder with Hyperactivity - drug therapy
Behavior, Animal - drug effects
Biological and medical sciences
Conditioning, Operant - drug effects
Discrimination Learning - drug effects
Dopamine Uptake Inhibitors - adverse effects
Drug addictions
Drug Interactions
Excitatory Amino Acid Antagonists - adverse effects
Male
Medical sciences
Motor Activity - drug effects
Neuropharmacology
Pharmacology. Drug treatments
Phencyclidine - adverse effects
Prefrontal Cortex - drug effects
Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer..., (alzheimer disease)
Psychology. Psychoanalysis. Psychiatry
Psychopharmacology
Random Allocation
Rats
Rats, Sprague-Dawley
Receptors, Dopamine D1 - agonists
Toxicology
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Summary:Repeated exposure to psychomotor stimulants can lead to sensitization to their effects, and sensitization has been implicated in the pathophysiology of schizophrenia and drug abuse. These disorders are characterized by cognitive deficits, particularly in prefrontally mediated executive function. The present experiments were conducted to investigate the effects of sensitizing regimens of amphetamine and phencyclidine (PCP) on attentional set shifting. Rats received injections of amphetamine, PCP or saline three times per week for 5 weeks. Four weeks later, rats were trained to dig for food in one of two bowls, each bowl having an odour and a texture. Only one dimension (odour or texture) correctly predicted which bowl was baited. Rats were then tested on a series of discriminations including those requiring an intra-dimensional shift (IDS), an extra-dimensional shift (EDS) or a reversal of previously relevant and irrelevant stimuli. Rats sensitized to amphetamine performed normally on the IDS, but were impaired on the EDS, as well as on reversal discriminations. PCP-sensitized rats were unaffected on any of the discriminations. In amphetamine-sensitized rats the deficit at the EDS stage was reversed by infusion of the D(1) receptor agonist SKF38393 into the medial prefrontal cortex (mPFC). Results show that the amphetamine-sensitized state impairs prefrontally mediated attentional set shifting. This is consistent with cognitive deficits in schizophrenia and addiction, and with the evidence that amphetamine sensitization is accompanied by functional changes in the mPFC. These results further add to a growing literature showing that activating D(1) receptors in the mPFC improves aspects of cognition.
ISSN:0033-3158
1432-2072
DOI:10.1007/s00213-005-0157-6