Genotyping of ADRB1 polymorphism (rs1801253)

The genomic DNAs of all the subjects were extracted from peripheral blood leukocytes using Gentra Systems Kit (Minneapolis, MN, cat # D5500). The DNA fragment containing codon 389 of the ARDB1 gene was amplified by polymerase chain reaction (PCR) using a sense primer (5’-CTCTTCGTCTTCTTCAACTGGCT-3′) and an antisense primer (5’-CAACAAGGAACATCAGCAAGC-3′). The PCR conditions consisted of an initial denaturation step at 95 °C for 15 min, followed by 34 cycles of denaturation at 95 °C for 1 min, annealing at 60 °C for 1 min, and extension at 72 °C for 1 min, with a final extension of 10 min at 72 °C. With these primers, a PCR product was verified on 2% agarose gel electrophoresis. Nucleotide sequencing was carried out by the ABI Big Dye Terminator protocol using ABI 3100 Avant Genetic Analyzer.