Role of vasoactive intestinal polypeptide (VIP) in the neurogenic vasodilatation of the portal vein in the rabbit
A coarse network of nerve fibres displaying immunoreactivity for vasoactive intestinal polypeptide (VIP) was found in the wall of the hepatic portal vein of the rabbit. Electrical field stimulation of the rabbit portal vein in vitro, in the presence of adrenergic and cholinergic blockade, caused a marked relaxation of the vessel and a release of VIP into the perfusate. Addition of VIP to the tissu