Influence of Blood Pressure and Blood Flow on the Activity of the Respiratory, Vasomotor and Cardio-Regulatory Centres

Abstract

THE classical opinion is that changes in the central blood flow and blood pressure affect and regulate in a direct central manner the activities of the respiratory and cardio-vascular centres: decrease of central blood pressure or blood flow was considered to stimulate directly the respiratory and vasomotor centres and to inhibit directly the tone of the vagal cardio-inhibitory centre; increase of central pressure or flow was considered to induce directly the opposite central reactions. Although numerous experiments performed by several different methods had shown1 that blood pressure and blood flow changes occurring in physiological and physio-pathological conditions affect the activities of the respiratory and cardiovascular centres not through a direct central action but only reflexly by way of the presso-receptor nerves of the aortic and carotid sinus areas, the classical theory of direct central regulation is still supported, particularly as regards the physiological control of the respiratory centre2. As this point is of fundamental theoretical importance, I have investigated the problem.