Stress-induced elevation of the ST segment in the rat electrocardiogram is normalized by an adrenoceptor blocker

1. Emotional stress is one of the aetiologies of cardiac accidents, but the precise mechanisms remain to be elucidated. In the present study we used the immobilization stress model in rats to investigate electrocardiographic (ECG) changes. 2. A rapid elevation of the ST segment at the II, III, aVF and precordial leads in the ECG was found and this returned to prestress basal levels after removal of stress. 3. This ECG change was normalized by combined blockade of alpha- and beta-adrenoceptors, but not by administration of a potent coronary vasodilator, such as a calcium channel blocker or nitroglycerin. 4. These results suggest that direct activation of cardiac adrenoceptors by stress may result in angina-like ECG changes.