Abstract
Sensitization to drugs, such as amphetamine, is associated with alterations in the morphology of neurons in the nucleus accumbens, a brain region critical to motivation and reward. The studies reported here indicate that a strong natural motivator, sodium depletion and associated salt appetite, also leads to alterations in neurons in nucleus accumbens. Medium spiny neurons in the shell of the nucleus accumbens of rats that had experienced sodium depletions had significantly more dendritic branches and spines than controls. In addition, a history of sodium depletions was found to have cross-sensitization effects, leading to enhanced psychostimulant responses to amphetamine. Thus, neuronal alterations common to salt and drug sensitization may provide a general mechanism for enhanced behavioral responses to subsequent exposures to these challenges.