BACKGROUND: The Dopamine D3 receptor (DRD3) gene is thought to be involvedin essential hypertension (EH) because dopamine inhibits renin secretion via this receptor and becausedisruption of the DRD3 gene increases blood pressure in mice. EH is a complex, polygenetic disease. Associationstudies using the candidate gene approach may provide important clues regarding the etiology of hypertensionand define a basis for further genetic investigation. Therefore we examined the association between theSer9Gly polymorphism in the DRD3 gene and EH. MATERIAL/METHODS: One hundred eighty-one patients withEH and 181 age-matched subjects with normal blood pressure were enrolled. Genomic DNA was extracted fromperipheral blood leukocytes. Polymerase chain reaction (PCR) was used to amplify the Ser9Gly polymorphicsite in the DRD3 gene, and restriction fragment length polymorphism (RFLP) analysis of the PCR productwas used to score the A and G alleles. Plasma renin activity and plasma aldosterone concentration weremeasured in untreated EH subjects. RESULTS: The genotype distribution was in Hardy-Weinberg equilibrium,and was not significantly different between the NT and EH groups. The frequencies of A and G alleleswere 0.674 (244/362) and 0.326 (118/362) for the NT group and 0.688 (249/362) and 0.312 (113/362) forthe EH group, respectively, and did not differ significantly between the two groups. The genotype didnot influence the plasma renin activity and aldosterone concentration in untreated EH patients. CONCLUSIONS:The Ser9Gly polymorphism in the DRD3 gene are not associated with EH. However, our negative result doesnot exclude the possibility of another variant elsewhere in or near the DRD3 gene in EH.

Keywords: Alleles, Genotype, Glycine, Hypertension, Japan, Leukocytes, Models, Genetic, Polymerase Chain Reaction, Polymorphism, Genetic, Polymorphism, Restriction Fragment Length, Receptors, Dopamine D2, Research Support, Non-U.S. Gov, Serine