Montrucchio G, Alloatti G, Tetta C, Roffinello C, Emanuelli G, Camussi G
Prostaglandins. 1986 Oct;32(4):539-54. doi: 10.1016/0090-6980(86)90036-5.
Platelet-activating factor (PAF) evoked myometrial contractions in two different patterns, depending on whether spontaneous activity was present. In spontaneously active myometrial strips (58%), both PAF and oxytocin enhanced the amplitude of myometrial contractions. In quiescent myometrial strips, PAF induced contractions characterized by a prompt development of tension, a plateau, and a final, rapid relaxation. In 54% of these strips, PAF-induced contraction was followed by rhythmic activity. PAF contractile response was dependent upon the concentration (0.1-100 nM); the minimal effective concentration of PAF was 0.1 nM and the EC50 was 1 nM. The response to oxytocin (0.01-10 mU/ml), assumed as reference stimulus, was characterized by a prompt development of tension, which was followed by a sustained, slow contraction and relaxation. PAF response was almost completely dependent on cyclooxygenase and partially on lipoxygenase pathways, as inferred from studies with indomethacin and FPL 55712, respectively. A receptor mediated mechanism of PAF action was suggested by specific desensitization of the myometrium to a second challenge with an equimolar concentration of PAF (but not with oxytocin) and the blocking effect of CV 3988, a specific PAF receptor antagonist.
血小板激活因子（PAF）可引发子宫肌层出现两种不同模式的收缩，这取决于子宫肌层是否存在自发活动。在有自发活动的子宫肌层条带中（58%），PAF和催产素均能增强子宫肌层收缩的幅度。在静止的子宫肌层条带中，PAF诱导的收缩表现为张力迅速升高、达到平台期并最终快速松弛。在这些条带中，54%的条带在PAF诱导的收缩后会出现节律性活动。PAF的收缩反应取决于浓度（0.1 - 100 nM）；PAF的最小有效浓度为0.1 nM，半数有效浓度（EC50）为1 nM。以催产素（0.01 - 10 mU/ml）作为参考刺激，其反应特点是张力迅速升高，随后是持续缓慢的收缩和松弛。分别从吲哚美辛和FPL 55712的研究推断，PAF的反应几乎完全依赖于环氧化酶途径，部分依赖于脂氧化酶途径。子宫肌层对等摩尔浓度的PAF（而非催产素）的第二次刺激产生特异性脱敏以及PAF特异性受体拮抗剂CV 3988的阻断作用，提示了PAF作用的受体介导机制。
