Conditions: Healthy
Keywords: Atenolol Exercise Genotype Healthy volunteers
Allocation: NA | Intervention model: SINGLE_GROUP
Enrollment: 154
Healthy volunteers: yes

Brief summary:
The overall goal of this project is to determine the genetic factors contributing to interindividual differences in response to beta-blockade.

Detailed description:
The Aim is to define the contribution of genetic variation to the interindividual variability in response to β-blockade. The rationale for the study is as follows: Beta-blockers prevent the activation of β-ARs and thus form the cornerstone of treatment of pathological states such as congestive heart failure and coronary artery disease. Functional polymorphisms in cardiac beta-receptors have been shown to determine response to β-blocker therapy. A physiologic stimulus such as exercise causes sympathetic stimulation and activation of the cardiac β-ARs and genotypic differences in response to β-blockers are magnified under states of heightened sympathetic activity. Thus, in addition to measuring the response to β-blockers at rest, we will also determine the response to β-blockade after sub-maximal exercise on a supine bicycle ergometer. Genetic variations that may alter sensitivity to a beta blocker will be sought.

Arms:
arm 1: There is only 1 arm to this study. Intervention: All participants received atenolol. Genotyping for GRK5 was performed to identify if participants were GLN/GLN, GLN/LEU, or LEU/LEU.

Heart rates were measured at rest, and as participants performed graded incremental exercise on a supine bicycle ergometer (at 25, 50, and 75 W for 2 minutes each) twice, once before and once 2.5 hours after taking 25 mg of atenolol.

Interventions: intervention 1: Atenolol (β-blocker)
Intervention descriptions: intervention 1: 25 mg tablet

Protocol document: