Mutant Taiep rats exhibit an increase in D1 binding in basal ganglia

Previous reports have shown that the Taiep rat develop a progressive neurological syndrome characterized by tremor, ataxia, immobility episodes, audiogenic seizures and hind limb paralysis. Here we have investigated whether differences in levels of dopamine D1-like and D2-like receptors could be correlated with the progression of this neurological syndrome. Comparative autoradiographic study of Taiep and Sprague-Dawley (SD) rats at level of basal ganglia and limbic subregion were undertaken in 3- and 9-month-old rats. The Taiep rats exhibited a higher level of D1 receptors in the basal ganglia subregions compared to SD. However, there were no differences in the level of D1 receptors in the limbic subregions between these two strains. As compared to the SD rats, the Taiep rats did not appear to change levels of D2-like receptors. These data suggest that the differences in D1 receptors in these two strains rats may in part contribute to develop the dopamine related symptoms seen in the mutant rat, such as tremor, which is the earliest sign of the Taiep rat syndrome.