Blunted humoral responses to mental stress and physical exercise in cardiac transplant recipients

Since recent results have suggested that the relative neuroendocrine response to physical activity is exaggerated following cardiac transplantation, we studied the haemodvnamic-neuroendocrine responses to mental stress, and to physical exercise, in heart transplant recipients free of antihypertensive medication. Ten patients were studied 17 years (mean) after transplantation and compared with 10 age-matched controls. Plasma levels of catecholamines, renin activity, aldosterone, atrial natriuretic factor, calcitonin gene-related pep tide (CGRP), and endothelin were measured, together with blood pressure and heart rate, during mental stress and graded, submaximal ergometry. Mental stress increased blood pressure in both groups (P