Figure 1

RT-PCR analysis of dopamine D ₁ -like receptors in human airway smooth muscle. Representative gel images of RT-PCR analysis of total RNA using primers specific for human dopamine D₁ receptor (A) and D₅ receptor (B). Total RNA extracted from freshly dissected human tracheal airway smooth muscle or primary cultures of human airway smooth muscle (HASM) cells was analyzed. Lanes 1: base pair standards; Lanes 2: negative control (no RNA); Lanes 3: total RNA from freshly dissected native human airway smooth muscle tissue; Lanes 4: total RNA from primary cultured HASM cells obtained from Lonza (Walkersville, MD); Lanes 5: total RNA from whole human brain. −RT; cDNA synthesis reactions performed in the absence of reverse transcriptase confirming that PCR products were not arising from contaminating genomic DNA.