[Summation of arterial pressure responses to simultaneous stimulation of the central ends of the two vagus nerves].

In anesthetized vagotomized cats, electrical stimulation of the n. vagus was followed by an increase or decrease of blood pressure (BP) and heart rate, and of responses of these parameters to simulation of the other n. vagus. On increase of the strength of stimulation the testing response had multiphase variations. Mean depressor response of BP changed in the same way as the conditioning stimulus, while the pressor response changed in the opposite way. The vasomotor center is concluded to have an autoregulation mechanism which maintains activity of the center by increasing or decreasing the sensitivity to vagal afferents.