THE ACTIVITY OF THE CARDIOREGULATORY AND ABDOMINAL SYMPATHETIC NERVES OF THE CAT IN THE BAINBRIDGE REFLEX

Abstract

In decerebrate and non-decerebrate cats the activity of the cardioregulatory and abdominal sympathetic nerves following venous infusion of saline solution was investigated by means of action potentials. Efferent impulses in the cardiac sympathetic nerve were inhibited by venous infusion. Such an effect was not abolished by cutting the sino-aortic nerves, but by cutting the vagi. Digital compression of the right or left atrial wall evoked a similar inhibition in the cardiac sympathetic nerve. The efferent impulses in the cardiac vagal nerve were increased by venous infusion. Such a response was not abolished by cutting the sino-aortic nerves, but by cutting the contralateral vagus nerve. The efferent impulses in the abdominal sympathetic nerves were inhibited by venous infusion. Such a response was not abolished by cutting the sino-aortic nerves, but by cutting the vagi. It is concluded that the cardiac vagal afferent impulses following venous infusion cause an increase of the cardiac vagal tone and a diminution of the accelerator and vasomotor tones, thus the true reflex response following venous infusion may be bradycardia and hypotension.