Background & aim: exposure to Bisphenol A (BPA) produces a significant increase in levels of the dopamine D1 receptor mRNA throughout the brain. Accordingly, the aim of present study was to investigate the effect of BPA on dopamine D1 receptor distribution in accumbens (aca) and caudate putamen (cpu) nuclei in with and without learning of male rats.

Methods: In the present experimental study, thirty male rats weighting 220- 300 g were used. Animals were divided into 6 groups, that each with 5 male rats. BPA in doses 5 and 50 mg/kg/day were used by oral intake for 15 days. Learning and memory were performed by a passive avoidance shuttle-box. Distribution of dopamine D1 receptor was investigated by immune-histochemical procedure. For determination of color difference the software of Image Analyzer were used. For data analysis, One-way ANOVA test and Tukey test as post-hoc were used (P<0.05).

Results: Data in the present study showed that BPA in two dose significantly (P<0.05) decrease distribution of dopamine D1 receptor in aca nucleus relative to sham2 of male rats with learning. BPA in two dose significantly (P<0.05) decrease distribution of dopamine D1 receptor in cpu nucleus relative to sham1 and 2 of male rats with and without learning. Distribution of dopamine D1 receptor in aca and cpu nuclei significantly (P<0.05) higher in sham 2 compared to sham1group. 

Conclusion: According to present results, BPA impair dopamine D1 receptor distribution in aca and cpu nuclei of male rats, while the BPA in learned animal has not significant effects on dopamine D1 receptor distribution.