Clark K E, Harrington D J
Prostaglandins. 1982 Feb;23(2):227-36. doi: 10.1016/0090-6980(82)90050-8.
Prostacyclin is a potent vasodilator in a number of vascular beds including the uterus. However, the role of prostacyclin in maintaining uterine blood flow during pregnancy is not well established. Recent reports have appeared suggesting that tranylcypromine can selectively inhibit prostacyclin synthesis. Thus, the present study was undertaken using an unanesthetized chronically catheterized pregnant sheep preparation to evaluate the effects of direct intra-arterial infusions of tranylcypromine on the uterine vasculature of late-term pregnant ewes. Infusions of 1,3 and 10 mg/min of tranylcypromine led to dose-related reduction in uterine blood flow (16, 21 and 47 percent, respectively) and increased blood pressure (7, 10 and 23 percent, respectively). However, these alterations were not associated with reductions in the uterine production rates of the prostacyclin metabolite, 6-keto-PGF1alpha, as determined by unextracted plasma RIA. In addition, pre-treatment of animals with the alpha-adrenergic blocking agent, phenoxybenzamine, almost totally abolished uterine and systemic blood pressure responses to tranylcypromine. These data suggest that tranylcypromine either releases or elevates levels of an alpha adrenergic stimulant which constricts the uterine and systemic vasculature and does not alter prostacyclin levels at the dose tested.
前列环素在包括子宫在内的许多血管床中是一种强效血管扩张剂。然而，前列环素在维持孕期子宫血流中的作用尚未完全明确。最近有报道称反苯环丙胺可选择性抑制前列环素的合成。因此，本研究采用未麻醉的、长期插管的怀孕绵羊制备模型，以评估经动脉直接输注反苯环丙胺对晚期妊娠母羊子宫血管系统的影响。输注速率为1、3和10mg/min的反苯环丙胺导致子宫血流量呈剂量依赖性减少（分别为16%、21%和47%），血压升高（分别为7%、10%和23%）。然而，通过未提取血浆放射免疫分析法测定，这些变化与前列环素代谢产物6-酮-前列腺素F1α的子宫生成率降低无关。此外，用α-肾上腺素能阻断剂酚苄明对动物进行预处理，几乎完全消除了子宫和全身血压对反苯环丙胺的反应。这些数据表明，反苯环丙胺要么释放或提高了一种α肾上腺素能兴奋剂的水平，该兴奋剂会使子宫和全身血管收缩，并且在所测试的剂量下不会改变前列环素水平。
