Modulation of vagus escape phenomenon by afferent vagal stimulation.

The present study was conducted on healthy adult mongrel dogs under chloralose urethane anaesthesia. After bilateral midcervical vagotomy, peripheral end of either vagus was stimulated continuously. This stimulation produced cardiac asystole followed by escape beats. Initially, the heart rate and arterial pressure were low, but both increased progressively and reached a steady-state level in 1-3 min while stimulation of peripheral vagus continued. During this plateau of vagus escape, stimulation of the central end of either vagus produced elevation of arterial pressure and cardio-acceleration. This modulation of vagus escape phenomenon by afferent vagal stimulation was reproducible.