The amphetamine sensitization model of schizophrenia: Relevance beyond psychotic symptoms?

Daria Peleg-Raibstein*, Benjamin K. Yee, Joram Feldon, Jonas Hauser

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

Abstract

Rationale: A sensitized dopamine system may be linked to the genesis of psychotic symptoms in schizophrenia. Following withdrawal from amphetamine exposures, psychotic-like traits have been robustly demonstrated, but the presence of cognitive/mnemonic deficits remains uncertain. Methods: Adult male Lewis and Fischer rats, differing in cognitive performance, were exposed intermittently to escalating doses of amphetamine over 5 weeks. This was effective in producing behavioral sensitization to a subsequent amphetamine challenge. Following 27 days of drug withdrawal, the animals were assessed in Pavlovian conditioning, object recognition, and spatial working memory. In addition, prepulse inhibition (PPI), spontaneous motor activity, and anxiety-like behavior were measured. Results: Amphetamine pretreatment induced behavioral sensitization in both rat strains similarly. Working memory was enhanced in Fischer but not Lewis rats following withdrawal. Spontaneous novel object preference was enhanced in sensitized Fischer rats, but was impaired in sensitized Lewis rats, thus effectively reversing the strain difference in non-sensitized controls. In contrast, Pavlovian fear conditioning remained unaffected and so were anxiety-like behavior, open field activity, and PPI. Conclusion: The face validity of the amphetamine withdrawal model for cognitive deficits was limited to the object recognition memory impairment observed in sensitized Lewis rats. Yet, the possibility that enhancing dopaminergic neurotransmission may facilitate object recognition and spatial working memory performance was demonstrated in sensitized Fischer rats. Identification of the mechanisms underlying such strain-dependent effects would be instrumental in the further specifications of the construct validity, and therefore the limitations and potential of the amphetamine sensitization model of schizophrenia.

Original languageEnglish
Pages (from-to)603-621
Number of pages19
JournalPsychopharmacology
Volume206
Issue number4
DOIs
StatePublished - Nov 2009
Externally publishedYes

Funding

FundersFunder number
Swiss Federal Institute of Technology
Eidgenössische Technische Hochschule Zürich

    Keywords

    • Amphetamine
    • Cognitive symptoms
    • Dopamine
    • Psychosis
    • Schizophrenia
    • Sensitization

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