![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
![[Contents]](/icons/banner/tocACT.gif){kind=icon}
|
|
|
|
|
||
RJ Altiere, JA Kiritsy-Roy and JD Catravas
Acetylcholine has been reported to produce vasodilation or vasoconstriction in the pulmonary circulation of different species. In rabbit lungs, acetylcholine is a potent vasoconstrictor. The present study was undertaken to examine the contractile effects of acetylcholine in arteries isolated from various regions of the rabbit pulmonary vascular bed and in thoracic aorta. Arteries isolated from within the lung were more responsive than extrapulmonary arteries (main pulmonary artery and aorta) to the contractile effects of acetylcholine. In vessels precontracted with norepinephrine, acetylcholine caused biphasic (relaxation-contraction) concentration- response curves. Atropine inhibited acetylcholine-induced contractions in all vessels, whereas pretreatment with cyclooxygenase or thromboxane synthetase inhibitors abolished contractile responses to acetylcholine only in intrapulmonary arteries. In accordance with these findings, acetylcholine caused a 3-fold increase in thromboxane A2 release from intrapulmonary arteries but not from extrapulmonary arteries. Inhibition of thromboxane synthetase abolished this effect of acetylcholine. Endothelium removal decreased contractile responses in intrapulmonary arteries but it did not decrease contractions in extrapulmonary arteries, suggesting that endothelium may contribute to acetylcholine-induced, thromboxane-mediated contractions in intrapulmonary arteries. Indomethacin did not inhibit contractile responses in endothelium-denuded main pulmonary artery or aorta but it abolished the weak contractile responses in intrapulmonary arteries without endothelium, indicating that arterial smooth muscle also was a source of contractile prostanoid biosynthesis enhanced by acetylcholine. These results demonstrate that acetylcholine contracts rabbit intrapulmonary arteries through generation of thromboxane A2 but that a different mechanism is responsible for mediating weaker acetylcholine-induced contractions in extrapulmonary artery and aorta.(ABSTRACT TRUNCATED AT 250 WORDS)
This article has been cited by other articles:
|
|
 |
|
  E. Toth, A. Racz, J. Toth, P. M. Kaminski, M. S. Wolin, Z. Bagi, and A. Koller Contribution of polyol pathway to arteriolar dysfunction in hyperglycemia. Role of oxidative stress, reduced NO, and enhanced PGH2/TXA2 mediation Am J Physiol Heart Circ Physiol, November 1, 2007; 293(5): H3096 - H3104. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Miller, K. Forrester, D. A. Hart, C. Leonard, P. Salo, and R. C. Bray Endothelial dysfunction and decreased vascular responsiveness in the anterior cruciate ligament-deficient model of osteoarthritis J Appl Physiol, March 1, 2007; 102(3): 1161 - 1169. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Zhu, M. Bousamra II, D. C. Zeldin, J. R. Falck, M. Townsley, D. R. Harder, R. J. Roman, and E. R. Jacobs Epoxyeicosatrienoic acids constrict isolated pressurized rabbit pulmonary arteries Am J Physiol Lung Cell Mol Physiol, February 1, 2000; 278(2): L335 - L343. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. I. Peinado, J. A. Barbera, J. Ramirez, F. P. Gomez, J. Roca, L. Jover, J. M. Gimferrer, and R. Rodriguez-Roisin Endothelial dysfunction in pulmonary arteries of patients with mild COPD Am J Physiol Lung Cell Mol Physiol, June 1, 1998; 274(6): L908 - L913. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Husain, N. P. Andrews, D. Mulcahy, J. A. Panza, and A. A. Quyyumi Aspirin Improves Endothelial Dysfunction in Atherosclerosis Circulation, March 3, 1998; 97(8): 716 - 720. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. Shi, D. H. Eidelman, and R. P. Michel Differential relaxant responses of pulmonary arteries and veins in lung explants of guinea pigs J Appl Physiol, November 1, 1997; 83(5): 1476 - 1481. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. L. Pfister and W. B. Campbell Reduced Pulmonary Artery Vasoconstriction to Methacholine in Cholesterol-Fed Rabbits Hypertension, March 1, 1996; 27(3): 804 - 810. [Abstract] [Full Text]
|
|
 |
 |
 |
|
 |
 |
 |
