Lead intoxication during intrauterine life and lactation but not during adulthood reduces nucleus accumbens dopamine release as studied by brain microdialysis

Environmentally relevant levels of lead (Pb) have been demonstrated to have a neurotoxic action, especially on children. In this study, Long-Evans rat s were continuously exposed to Pb acetate in drinking water from early gest ational days (2-6) or from 28 days of age. At the 13th week of age, the fun ctional activity of the nucleus accumbens (NAC) dopaminergic system was stu died by means of transversal microdialysis. Neither Pb treatment regimen mo dified dopamine (DA) and 3.3-dihydroxyphenylacetic acid (DOPAC) extracellul ar concentrations. with respect to control rats. However, neuronal depolari sation, induced by perfusion with 60 mM KCl, increased extracellular DA lev els to a significantly minor degree in rats exposed to Pb during the intrau terine life. with respect to both control and adult Ph treated rats. The in utero treated rats also responded with a lower DA release to amphetamine(l mg,kg ip) administration. On the other hand. no difference in NAC DA level was found amongst treatment groups in response to different concentrations of the D,D, dopaminergic agonist quinpirole. locally administered by means of inverse dialysis. These data indicate a preferential impairment of NAC DA synthesis acid/or release in rats exposed to Pb acetate during their int rauterine life. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.