Do adaptive changes in ECG, in response to voluntary exercise training, reflect changes in myocardial ion channel gene expression and single myocyte electrophysiology? (360G-Wellcome-078149_Z_05_Z)

We wish to understand how exercise benefits the heart. We have a rat model of voluntary exercise that results in cardiac ventricular and myocyte hypertrophyand modification of the electrical properties of single myocytes. These effects are dependant upon the regional origin of the myocytes within the leftventricular wall.We now wish to test whether whole heart electrophysiology andion channel gene expression is altered in a manner consistent with these cellular changes. We will measure the adaptive changes in the ECG at rest and during voluntary exercise in conscious, unrestrained animals using telemetry. Using PCR arrays on the same, isolated hearts we will then identify the ion channel and hypertrophy marker genes that respond to voluntary exercise. This approach will allow us to link levels of activity with adaptive changes in ECG, cardiac growth and gene expression profiles for each individual animal. We will also determine whether these changes are cardioprotective, making the model less prone to arrhythmias. Key goalsi) Linking voluntary exercise-induced changes in whole heart electrophysiology and ion channel gene