Martin S E, Kuvin J T, Offenbacher S, Odle B M, Patterson R E
Carlyle Fraser Heart Center, Crawford Long Hospital, Emory University, Atlanta, Georgia.
Am J Physiol. 1992 Oct;263(4 Pt 2):H1045-53. doi: 10.1152/ajpheart.1992.263.4.H1045.
We previously reported that coronary constriction following neuropeptide Y (NPY) was alleviated by cyclooxygenase blockade. To determine the role of thromboxane A2 (TxA2), anesthetized dogs received two paired doses of NPY given 2 h apart. Nine control dogs received NPY alone. Nine test dogs received one of three TxA2 receptor antagonists given between the doses of NPY. Also, five dogs received NPY during which prostaglandins were measured. In controls, NPY decreased coronary blood flow and increased aortic pressure; coronary resistance was increased significantly. Heart rate fell, and myocardial oxygen consumption was unchanged. Thromboxane receptor blockers significantly relieved the coronary constrictor effect of NPY. The reduction in coronary blood flow was blunted, while heart rate, first derivative of left ventricular pressure, and myocardial oxygen consumption were unchanged. Alleviation by TxA2 receptor blockade paralleled that reported for cyclooxygenase inhibitors. Also, significant increases in coronary venous TxA2 were seen at the time of maximal increases in coronary resistance, while prostacyclin was unchanged. In summary, TxA2 appears to mediate part of the coronary constrictor effect of NPY.
我们之前报道过，环氧化酶阻断可减轻神经肽Y（NPY）引起的冠状动脉收缩。为了确定血栓素A2（TxA2）的作用，对麻醉犬每隔2小时给予两剂配对的NPY。9只对照犬单独接受NPY。9只试验犬在NPY剂量之间接受三种TxA2受体拮抗剂之一。此外，5只犬接受NPY期间测量了前列腺素。在对照组中，NPY降低了冠状动脉血流量并升高了主动脉压；冠状动脉阻力显著增加。心率下降，心肌耗氧量未变。血栓素受体阻滞剂显著减轻了NPY的冠状动脉收缩作用。冠状动脉血流量的减少受到抑制，而心率、左心室压力的一阶导数和心肌耗氧量未变。TxA2受体阻断的减轻作用与环氧化酶抑制剂的报道相似。此外，在冠状动脉阻力最大增加时，冠状动脉静脉TxA2显著增加，而前列环素未变。总之，TxA2似乎介导了NPY冠状动脉收缩作用的一部分。
