Glutamate and dopamine in nucleus accumbens core and shell; sequence learning vs. performance

BAUTER, M.R.; BROCKEL, B.J.; PANKEVICH, D.E.; VIRGOLINI, M.B.; CORY-SLECHTA, D.A

ELSEVIER SCIENCE BV

Año: 2003 vol. 24 p. 227 - 227

This study sought to determine whether neurochemical changes associated with chronic postweaning lead (Pb)exposure, namely, enhanced dopamine (DA) activity and/or blockade of NMDA function in nucleus accumbens (NAC),underlie the learning impairments also associated with this Pb regimen, and whether core or shell subregions of nucleus accumbens would be more important to such effects. If so, then mimicking these neurochemical changes in normal (control) rats should reproduce these Pb-induced learning impairments. For this purpose, the effects of DA (20?80 mg), the non-competitive NMDA antagonist MK-801 (1.0?2.5 mg) or DA þ MK-801 (40 þ 1:0, 80 þ 2:5 mg) were infused in core or shell of nucleus accumbens in normal rats and effects on a multiple schedule of repeated learning (RL) and performance (P) evaluated. In core, MK-801 mimicked the effects of Pb exposure, selectively reducing RL accuracy with no corresponding changes in P accuracy, an effect derived from an increase