Barnes P J, Cadieux A, Carstairs J R, Greenberg B, Polak J M, Rhoden K
Br J Pharmacol. 1986 Sep;89(1):157-62. doi: 10.1111/j.1476-5381.1986.tb11131.x.
The role of vasoactive intestinal peptide (VIP) in the control of pulmonary vascular tone was investigated by functional response, immunocytochemical localisation and receptor autoradiography in bovine pulmonary arteries. VIP-immunoreactive nerve fibres were present at the adventitial-medial junction and in the media of the vessels. Exposure of precontracted bovine pulmonary artery segments to VIP in vitro resulted in almost complete (86 +/- 3%; mean +/- s.e.mean) relaxation, the concentration needed for 50% relaxation being 4.47 +/- 0.37 X 10(-9)M. VIP effects did not depend on the presence of intact endothelial cells. The distribution of VIP receptors was studied by autoradiography using [125I]-VIP. A high density of VIP receptors was found in arterial vascular smooth muscle, with a gradient of density from adventitia to luminal surface. There were no receptors on endothelial cells. These data show that VIP is a potent vasodilator of bovine pulmonary arteries, via direct activation of VIP receptors in vascular smooth muscle. VIP-immunoreactive nerves may influence pulmonary vascular tone directly and could, therefore, be important in regulating pulmonary blood flow.
通过对牛肺动脉进行功能反应、免疫细胞化学定位和受体放射自显影，研究了血管活性肠肽（VIP）在控制肺血管张力中的作用。VIP免疫反应性神经纤维存在于血管外膜-中膜交界处和血管中膜。在体外，将预先收缩的牛肺动脉段暴露于VIP会导致几乎完全（86±3%；平均值±标准误平均值）的舒张，50%舒张所需的浓度为4.47±0.37×10⁻⁹M。VIP的作用不依赖于完整内皮细胞的存在。使用[¹²⁵I]-VIP通过放射自显影研究了VIP受体的分布。在动脉血管平滑肌中发现了高密度的VIP受体，从外膜到管腔表面存在密度梯度。内皮细胞上没有受体。这些数据表明，VIP通过直接激活血管平滑肌中的VIP受体，是牛肺动脉的一种强效血管舒张剂。VIP免疫反应性神经可能直接影响肺血管张力，因此在调节肺血流中可能很重要。
