Systemic or intra-accumbens injection of D-amphetamine delays habituation to a tone stimulus in rats.
Dopamine release within the nucleus accumbens shell is suggested to control the salience of environmental stimuli, and previous research has shown that the indirect dopamine agonist D-amphetamine can alter the salience of both aversive and neutral stimuli. In experiment 1, the effect of systemic injection of D-amphetamine (0.5, 1 mg/kg) on fear conditioning to a tone was assessed in an 'off-baseline' conditioned suppression procedure using several footshock intensities. Although the effects of amphetamine on conditioning were unclear, the results indicated a deficit of simple tone habituation in amphetamine-treated rats. In experiment 2, habituation of the orienting reaction to a tone was assessed by the progressive reduction of lick suppression upon repeated presentation of the auditory stimulus. D-Amphetamine delayed tone habituation, whether administered systemically (0.5, 1 mg/kg) or into the nucleus accumbens shell (3, 10 microg/0.5 microl). These data are consistent with electrophysiological and neurochemical data demonstrating the role of nucleus accumbens dopamine in novelty processing. The relevance of the data to latent inhibition is discussed.
Dieu
Y
Y
Laboratoire de Neurosciences Comportementales et Cognitives (UMR 7521 ULP/CNRS), 12 rue Goethe, 67000 Strasbourg, France.
Seillier
A
A
Majchrzak
M
M
Marchand
A
A
Di Scala
G
G
D000161:Acoustic Stimulation; D000818:Animals; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000494:pharmacology*; D003213:Conditioning, Psychological / Q000187:drug effects; D003913:Dextroamphetamine / Q000008:administration & dosage / Q000494:pharmacology*; D005108:Extinction, Psychological / Q000187:drug effects; D005239:Fear / Q000187:drug effects; D006185:Habituation, Psychophysiologic / Q000187:drug effects*; D007274:Injections, Intraperitoneal; D008297:Male; D008845:Microinjections; D009714:Nucleus Accumbens; D051381:Rats; D020318:Rats, Long-Evans
D000697:Central Nervous System Stimulants; D003913:Dextroamphetamine