Afferent pathway of systemic pressor response to proximal vagosympathetic stimulation in the dog

¹ Department of Surgery, Veterans Administration Hospital, and University of Minnesota, Minneapolis, Minnesota

The systemic pressor response to stimulation of the cephalic end of the divided vagosympathetic trunk was studied 1–3 weeks after unilateral stellate ganglionectomy and upper thoracic sympathectomy in 14 dogs. In addition, in four of the animals blood flow to the circulatorily isolated head was measured using either the carotid or veterbral arteries alone for perfusion. In response to electrical stimulation of the proximal vagus, blood flow to the head decreased on the average of 21% on the sympathectomized side and by 55% on the intact side. Nevertheless, the average pressor response as measured in the femoral artery was not significantly altered by sympathectomy in either group. The data are interpreted as indicating that the aforementioned pressor response is mediated by way of afferent visceral fibers in the vagus nerve.