Extrinsic innervation of the canine superior vena cava, pulmonary, portal and renal veins.

The responses of the superior vena cava, portal, pulmonary, and renal veins to electrical stimulation of sympathetic nerves were investigated in dog. The vascular response was measured by the method with an intravascular cuff. The contractile responses to neural stimuli were mediated mainly by adrenergic mechanism in the four veins and that of the portal vein was, in addition, mediated in part by cholinergic one. The latter mechanism was also found in some cases of the pulmonary vein. As for the superior vena cava and the left renal vein the right-side dominancy in innervation was observed. These observations suggest a possible correlation between the embryogenesis of vein and its innervation.