Related Experiment Videos
Adrenergic-cholinergic interaction that modulates repolarization in the atrium is altered with aging
Eugene A Sosunov1, Evgeny P Anyukhovsky, Michael R Rosen
1Center for Molecular Therapeutics, Department of Pharmacology, College of Physicians and Surgeons of Columbia University, New York, New York 10032, USA.
Journal of Cardiovascular Electrophysiology
|May 30, 2002
Summary
Aging alters autonomic nervous system function, affecting heart rhythm. In older dogs, beta-adrenergic stimulation less effectively counteracts acetylcholine
Area of Science:
- Cardiovascular Physiology
- Autonomic Nervous System
- Cardiac Electrophysiology
Background:
- Aging is linked to autonomic nervous system decline.
- Senescence alters adrenergic and cholinergic stimulation effects.
- Age-related changes in autonomic function may predispose to arrhythmias.
Purpose of the Study:
- To investigate age-related changes in adrenergic-cholinergic interaction in atrial tissue.
- To determine how aging affects the interplay between beta-adrenergic and muscarinic agonists on cardiac action potentials.
Main Methods:
- Microelectrode recordings of action potentials from canine Bachmann's bundles.
- Comparison of adult (3-5 years) and old (8-12 years) dogs.
- Assessment of acetylcholine and isoproterenol effects, alone and combined.
Main Results:
- Older atria exhibited longer action potential duration (APD) at baseline.
- Acetylcholine more prominently shortened APD in old atria.
- Beta-adrenergic stimulation's ability to counteract acetylcholine-induced APD shortening decreased with age.
Conclusions:
- In adult hearts, beta-adrenergic stimulation acts as a brake against cholinergic-induced APD shortening.
- This antagonistic effect diminishes with age, potentially altering the arrhythmogenic substrate.
- Age-related decline in this interaction may contribute to increased arrhythmia susceptibility.