Identification of dopamine D4 receptor mRNA in circulating human lymphocytes using nested polymerase chain reaction

There is a long standing controversy if dopamine receptors are present on human lymphocytes. In recent years the expression of dopamine D3 and D5 receptors was demonstrated with molecular biological methods. Using reverse transcription and polymerase chain reaction (RT-PCR) we were able to demonstrate the expression of the dopamine D4 receptor (DRD4) mRNA in human circulating lymphocytes. Direct sequencing of the RT-PCR product assured that it corresponds to the human DRD4 sequence. However, because of the unusual high G/C content of the DRD4, several precautions have to be applied for reliable results.