Beta-2 adrenergic receptor gene variations and blood pressure under stress in normal twins.

We tested the hypothesis that blood pressure (BP) responses to physical and mental stress are associated with polymorphisms in the beta-2 adrenergic receptor (AR) gene. We studied normotensive, young, monozygotic (MZ) and dizygotic (DZ) twins. The subjects underwent automated BP measurements at the brachial and digital arteries and were subjected to mental arithmetic and cold pressor stress. We used allele-specific PCR to genotype four single nucleotide polymorphisms in the beta-2 AR gene. The most functionally relevant polymorphism in the beta-2 AR gene, Arg16/Gly, was associated with systolic and diastolic BP under resting conditions, during mental arithmetic, and during the cold pressor test, as well as with the increase in diastolic BP during both forms of stress. These findings support a role for the beta-2 AR gene in BP regulation. They also indicate that the beta-2 AR gene influences the level of not only resting but also stress-related BP.