AMPA-receptor involvement in c-fos expression in the medial prefrontal cortex and amygdala dissociates neural substrates of conditioned activity and conditioned reward.
Exposure to an environment, previously conditioned to amphetamine (1 mg/kg, i.p.), induced locomotor activity and c-fos expression (a marker for neuronal activation) in the mouse medial prefrontal cortex (mPFC) and amygdala; acute or repeated amphetamine (1 mg/kg, i.p.) administration induced c-fos expression additionally in the nucleus accumbens. An alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)-receptor antagonist, 2, 3-dihydroxy-6-nitro-7-sulphamoyl-benzo(f)quinoxaline (NBQX), blocked expression of conditioned activity, and prevented the increase in c-fos expression in mPFC, implicating mPFC AMPAergic transmission in the conditioned component of behavioural sensitization to amphetamine. NBQX failed to block the expression of amphetamine-conditioned place preference, a measure of conditioned reward, or conditioned c-fos expression in the amygdala, an area implicated in the expression of conditioned place preference. These findings indicate that the conditioned components of behavioural sensitization depend on AMPA-receptor-mediated activation in mPFC, but that conditioned reward does not.
Mead
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Laboratory of Experimental Psychology, School of Biological Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK.
Vasilaki
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Spyraki
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Duka
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Stephens
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D000679:Amygdala / Q000502:physiology*; D000818:Animals; D002755:Choice Behavior / Q000187:drug effects / Q000502:physiology*; D003216:Conditioning, Operant / Q000502:physiology*; D003913:Dextroamphetamine / Q000494:pharmacology*; D005786:Gene Expression Regulation; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D009714:Nucleus Accumbens / Q000502:physiology; D017397:Prefrontal Cortex / Q000502:physiology*; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis / Q000235:genetics*; D011810:Quinoxalines / Q000494:pharmacology*; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors / Q000502:physiology*; D012201:Reward
D016760:Proto-Oncogene Proteins c-fos; D011810:Quinoxalines; D018091:Receptors, AMPA; C062865:2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline; D003913:Dextroamphetamine