Nucleus accumbens AMPA receptor involvement in cocaine-conditioned place preference under different dietary conditions in XXXX .

@entity35 @entity4860 @entity139
RATIONALE: When ad libitum-fed (AL) @entity35 undergo cocaine place preference conditioning (CPP) but are switched to food restriction (FR) for testing, CPP is enhanced and preference scores correlate with phosphorylation of a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor @entity4860 at Ser845 in nucleus accumbens (NAc) core. OBJECTIVES: The present study tested whether a similar association exists in AL @entity35 and whether an inhibitor of Ca(2+)-permeable AMPARs blocks CPP expression in either diet group. MATERIALS AND METHODS: In experiments 1-3, AL @entity35 were conditioned with cocaine (12.0  mg/kg, i.p.). Three weeks later, CPP was tested daily and brains were harvested after the fifth test. Western analyses were used to probe for levels of AMPA receptors in NAc. In experiment 4, AL @entity35 were conditioned, half were switched to FR for testing, and half in each diet group received NAc core microinjection of 1-naphthylacetyl spermine (NASPM (NASPM) (25.0   g) prior to each test. RESULTS: In experiment 1, CPP expression in AL @entity35 was associated with elevated pSer845- @entity4860 , @entity4860 , and @entity139 in NAc. In experiment 2, the correlation between pSer845- @entity4860 and CPP was localized to NAc core. In experiment 3, pSer845- @entity4860 following a CPP test was higher in NAc synaptic membranes of FR relative to AL @entity35 . In experiment 4, NASPM blocked CPP expression in both diet groups. CONCLUSIONS: Results support a scheme in which pSer845- @entity4860 in NAc core underlies expression of cocaine CPP and does so by stabilizing or trafficking Ca(2+)-permeable AMPARs to the synaptic membrane. The more robust CPP of FR @entity35 may result from upregulation of stimulus-induced pSer845- @entity4860 .
