Sodium depletion and aldosterone decrease dopamine transporter activity innucleus accumbens but not striatum

Motivated behaviors, including sodium (Na) appetite, are correlated with in creased dopamine (DA) transmission in the nucleus accumbens (NAc). DA trans porter (DAT) modulation affects DA transmission and may play a role in moti vated behaviors. In vivo Na depletion, which reliably induces Na appetite, was correlated with robust decreases in DA uptake via the DAT in the rat NA c with rotating disk electrode voltammetry [1,277 +/- 162 vs. 575 +/- 89 pm ol . s(-1) . g(-1); V-max of transport for control vs. Na-depleted tissue]. Plasma aldosterone (Aldo) levels increase after in vivo Na depletion and c ontribute to Na appetite. Decreased DAT activity in the NAc was observed af ter in vitro Aldo treatment (428 +/- 28 vs. 300 +/- 25 pmol . s(-1) . g(-1) ). Neither treatment affected DAT activity in the striatum. These results s uggest that a direct action of Aldo is one possible mechanism by which Na d epletion induces a reduction in DAT activity in the NAc. Reduced DAT activi ty may play a role in generating increased NAc DA transmission during Na ap petite, which may underlie the motivating properties of Na for the Na-deple ted rat.