Transient disruption of attentional performance following escalating amphetamine administration in rats.
BACKGROUND
Attentional deficits are thought to be critically involved in the development of positive symptoms in schizophrenia. The present experiment tests the general hypothesis that sensitization of the mesolimbic dopaminergic system contributes to the attentional deficits in schizophrenia.


OBJECTIVE
The present study assessed attentional performance following administration of an escalating amphetamine regimen and subsequent "challenge" amphetamine administration in rats.


METHODS
Rats were trained to perform a two-lever sustained attention task that involved discrimination of visual signals and no signal presentation. After reaching criterion, subjects were assigned to receive escalating amphetamine or saline. Attentional performance was assessed immediately following escalating amphetamine, following "challenge" amphetamine administration (1.0 mg/kg) to amphetamine-pretreated rats, and for 3 days after the challenge session. At the end of this experiment, a dose-response study was conducted with saline-pretreated rats to confirm the appropriateness of the challenge dose.


RESULTS
Amphetamine-pretreated animals demonstrated a transient increase in errors on nonsignal trials following escalating amphetamine administration. The latency to press a lever was decreased during and after challenge amphetamine administration. Administration of 1.0 mg/kg amphetamine did not alter accuracy of amphetamine-pretreated animals or of saline-pretreated animals in the dose-response experiment.


CONCLUSIONS
Prior escalating amphetamine administration transiently disrupted attention, increasing incorrect "claims" for a signal on trials when no signal was presented. The present data support the existing literature that escalating amphetamine regimens may be useful to model the attentional deficits that contribute to the psychotic symptoms in schizophrenia.
Kondrad
Robyn L
RL
Department of Psychology, College of William and Mary, Williamsburg, VA 23187, USA.
Burk
Joshua A
JA
D000661:Amphetamine / Q000494:pharmacology*; D000818:Animals; D001288:Attention / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D008297:Male; D011597:Psychomotor Performance / Q000187:drug effects; D051381:Rats; D020318:Rats, Long-Evans
D000697:Central Nervous System Stimulants; D000661:Amphetamine