Social isolation after a single defeat reduces striatal dopamine transporter binding in rats

A single social defeat in male rats has long lasting physiological and beha vioural consequences, which are similar to those seen in depressive patient s. In addition, the housing conditions after social defeat appear to be cru cial for the development of depression-like symptoms. Because the dopaminer gic system is thought to be altered in depressive illness, we investigated the impact of individual and group housing on the temporal development of c hanges of dopamine transporter (DAT) binding in male rats after a single so cial defeat. The number of striatal DAT binding sites was reduced in animal s that remained isolated after being defeated. The isolation length after s ocial defeat amplified this effect, indicating a temporal development of th e changes on the striatal DAT. In animals which returned to the familiar gr oup after social defeat the density of striatal DAT binding sites was not a ffected. We conclude that social isolation after a single defeat reduces th e number of DAT binding sites. In contrast, a familiar environment after a single social defeat appears to prevent the stress-induced alterations on t he dopaminergic system. This finding suggests that housing conditions are c ritical when investigating the central nervous effects of social defeat in male rats.