Figure 1. The dopamine D₁ receptor was expressed in RGC-5 cells. A: Total mRNA was extracted from RGC-5 cells, and an amplicon of about 215 bp was obtained by RT–PCR using specific primers designed according to the cDNA sequence of the D₁ receptor. B: D₁ receptor protein from RGC-5 cell lysate was analyzed with western blot. Con: control, SKF: treated with 30 μM SKF83959, positive: positive control (lysate from mouse brain homogenate). A specific D₁ receptor protein band with a molecular weight of approximately 50 kDa was detected. Treatment with SKF83959 had no significant influence on the expression of the D₁ receptor related to the internal control, β-actin. A representative blot is shown from at least three independent experiments. C: Analysis and comparison of D₁ receptor amplicons were performed using the BLAST tool (NCBI online). The maximum identification was highlighted with a pink rectangle.