Wednesday, November 26, 2008JOHNSON CITY – A grant from the American Heart Association is helping a researcher at East Tennessee State University’s James H. Quillen College of Medicine better understand how a person’s heart rate and rhythm can be altered by cardiovascular disease.
“Primarily, control of heart rate is the responsibility of the nervous system,” said Dr. Donald Hoover, professor of Pharmacology, who explained that those nerves called the excitatory and inhibitory nerves help adjust the rate of heart beating to match needs imposed by daily activities.
But that vital input from the inhibitory nerves is altered among many patients who have heart disease, and, for them, the resulting imbalance elevates the risk of atrial arrhythmias and possibly fatal ventricular arrhythmias.
Understanding the factors that maintain the structure and function of inhibitory nerves in the heart is a goal of Hoover’s study.
“A protein called neurturin is critical for the development of most cardiac inhibitory nerve cells and nerve fibers,” Hoover said. “In animal models, we have observed that a deficiency of neurturin is associated with a compromised inhibitory control of heart rate.
“We believe there are other neurotrophic proteins that may also influence inhibitory neurons in the heart, and one of the study goals is to specifically identify these. This is important because these proteins have not been tested on the heart.”
Earlier studies from Hoover’s lab have observed cardiac inhibitory nerve growth in mice with type 1 diabetes. Hoover looks to identify the neurotrophic factors in these animal models and determine if they could be a stimulus for inhibitory nerve growth.
The research team will also be studying how cardiac nerves repair themselves in heart disease and determine the important molecules that control these changes.
Hoover believes a better understanding of the nerves that control the heart may ultimately lead to the development of new drugs that could prevent or reverse damage of the cardiac inhibitory nerves.