Genetic Variation of the Beta-2 Adrenergic Receptor and the Phenylethanolamine N-Methyltransferase Enzyme: Influence on Catecholamines, Cardiovascular Regulation, and the Cardiopulmonary Response to Albuterol
AuthorMartinez, Marina G.
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PublisherThe University of Arizona.
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AbstractHypertension, or chronic blood pressure elevation, affects approximately a third of American adults and is responsible for $70 billion dollars annually in medical costs. Recent studies have attempted to identify genetic variants that influence cardiopulmonary function, including blood pressure regulation. This study seeks to determine whether a polymorphism in position -182 of the gene encoding the phenylethanolamine N-methyltransferase (PNMT) enzyme, which converts norepinephrine to epinephrine, influences catecholamine levels and cardiovascular function. Secondly, this study seeks to explore whether a polymorphism at amino acid position 16 of the beta-2 adrenergic receptor (B2AR) affects the cardiovascular response to albuterol in healthy individuals; this study also explores the pulmonary response to albuterol in healthy subjects and patients with cystic fibrosis according to B2AR genotype. All subjects were genotyped and stratified according to genotype. Baseline measurements were taken. Albuterol was administered via nebulizer. Cardiopulmonary measurements were taken again at 30-, 60-, and 90- minutes post-albuterol administration. This study found that the PNMT polymorphism at position -182 influences circulating epinephrine, the epinephrine:norepinephrine ratio, and cardiac output. The B2AR polymorphism at amino acid position 16 affects the percent change in systemic vascular resistance in response to albuterol administration in healthy subjects. Furthermore, this study found that the B2AR polymorphism at amino acid 16 affects the change in forced vital capacity following albuterol administration in cystic fibrosis subjects.
Degree ProgramGraduate College