HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 99/5/1776    most recent 00469.2005v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (13) Citing Articles via Google Scholar Google Scholar Articles by Eisenach, J. H. Articles by Joyner, M. J. Search for Related Content PubMed PubMed Citation Articles by Eisenach, J. H. Articles by Joyner, M. J.

Arg16/Gly ₂-adrenergic receptor polymorphism alters the cardiac output response to isometric exercise

Departments of ¹Anesthesiology, ²Biostatistics, and ³Internal Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota

Submitted 25 April 2005 ; accepted in final form 28 June 2005

Normotensive adults homozygous for glycine (Gly) of the Arg16/Gly ₂-adrenergic-receptor polymorphism have 1) greater forearm ₂-receptor mediated vasodilation and 2) a higher heart rate (HR) response to isometric handgrip than arginine (Arg) homozygotes. To test the hypothesis that the higher HR response in Gly16 subjects serves to maintain the pressor response [increased cardiac output (CO)] in the setting of augmented peripheral vasodilation to endogenous catecholamines, we measured continuous HR (ECG), arterial pressure (Finapres), and CO (transthoracic echocardiography) during isometric, 40% submaximal handgrip to fatigue in healthy subjects homozygous for Gly (n = 30; mean age ± SE: 30 ± 1.2, 13 women) and Arg (n = 17, age 30 ± 1.6, 11 women). Resting data were similar between groups. Handgrip produced similar increases in arterial pressure and venous norepinephrine and epinephrine concentrations; however, HR increased more in the Gly group (60.1 ± 4.3% increase from baseline vs. 45.5 ± 3.9%, P = 0.03), and this caused CO to be higher (Gly: 7.6 ± 0.3 l/m vs. Arg: 6.5 ± 0.3 l/m, P = 0.03), whereas the decrease in systemic vascular resistance in the Gly group did not reach significance (P = 0.09). We conclude that Gly16 homozygotes generate a higher CO to maintain the pressor response to handgrip. The influence of polymorphic variants in the ₂-adrenergic receptor gene on the cardiovascular response to sympathoexcitation may have important implications in the development of hypertension and heart failure.

₂-adrenergic receptors; hypertension; genomics; sympathetic nervous system

This article has been cited by other articles:

				E. M. Snyder, K. C. Beck, S. T. Turner, E. A. Hoffman, M. J. Joyner, and B. D. Johnson Genetic variation of the beta2-adrenergic receptor is associated with differences in lung fluid accumulation in humans J Appl Physiol, June 1, 2007; 102(6): 2172 - 2178. [Abstract] [Full Text] [PDF]

				E. M. Snyder, S. T. Turner, M. J. Joyner, J. H. Eisenach, and B. D. Johnson The Arg16Gly polymorphism of the {beta}2-adrenergic receptor and the natriuretic response to rapid saline infusion in humans J. Physiol., August 1, 2006; 574(3): 947 - 954. [Abstract] [Full Text] [PDF]

				J. H. Eisenach, D. R. Schroeder, T. L. Pike, C. P. Johnson, W. G. Schrage, E. M. Snyder, B. D. Johnson, V. D. Garovic, S. T. Turner, and M. J. Joyner Dietary sodium restriction and {beta}2-adrenergic receptor polymorphism modulate cardiovascular function in humans J. Physiol., August 1, 2006; 574(3): 955 - 965. [Abstract] [Full Text] [PDF]

				C. Bell, N. R. Stob, and D. R. Seals Thermogenic responsiveness to nonspecific beta-adrenergic stimulation is not related to genetic variation in codon 16 of the beta2-adrenergic receptor Am J Physiol Endocrinol Metab, April 1, 2006; 290(4): E703 - E707. [Abstract] [Full Text] [PDF]