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Vasoactive intestinal peptide in bovine pulmonary artery: localisation, function and receptor autoradiography
Author(s) -
Barnes Peter J.,
Cadieux Alain,
Carstairs Jill R.,
Greenberg Barry,
Polak Julia M.,
Rhoden Kerry
Publication year - 1986
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1986.tb11131.x
Subject(s) - vasoactive intestinal peptide , adventitia , receptor , endocrinology , medicine , vasodilation , pulmonary artery , vascular smooth muscle , blood vessel , biology , endothelium , neuropeptide , chemistry , anatomy , smooth muscle
1 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. 2 VIP‐immunoreactive nerve fibres were present at the adventitial‐medial junction and in the media of the vessels. 3 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 × 10 −9 M. VIP effects did not depend on the presence of intact endothelial cells. 4 The distribution of VIP receptors was studied by autoradiography using [ 125 I]‐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. 5 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.