Suzuki R, Yoshino H, Kobayashi S
Department of Ophthalmology, Yamaguchi University School of Medicine, Ube, Japan.
Doc Ophthalmol. 1989 Jun;72(2):129-39. doi: 10.1007/BF00156703.
The function and sites of action of prostaglandins (PGs) vary in different animal species and tissues. In this study the influence of PGs (E1, E2, F2 alpha, D2) on muscle tone and nerve-mediated contraction was investigated in isolated bovine iris sphincter muscles. None of these PGs exogenously applied influenced the neuromuscular transmission. By contrast, after treatment with indomethacin, all PGs tested contracted the muscle much more than in the absence of indomethacin and under these conditions the PGs potentiated responses to cholinergic nerve stimulation. Their ED50 were (2.2 +/- 0.2) x 10(-7) M for PGE1, (6.7 +/- 0.3) x 10(-8) M for PGE2, and (7.3 +/- 0.4) x 10(-8) M for PGF2 alpha. PGE1 acted both on nerves and the muscle cell. PGE2 had its influence mostly via nerves. Whereas PGF2 alpha was less potent in the absence of indomethacin, PGF2 alpha had much more potent action primarily on nerves and partly on muscles after treatment with indomethacin. High concentrations of PGD2 had both pre- and post-junctional action with accompanying weak contraction of the muscle. Thus the degrees of pre- and post-junctional involvement were different from one another. There is a possibility that the application of these PGs alone masked the role of such endogenous agents. In order to understand and clarify the site and action of PGs, pretreatment with indomethacin may be useful in the iris muscle. In conclusion, PGs modulate cholinergic activity in the bovine iris sphincter muscles, as well as regulate the muscle tone.
前列腺素（PGs）的功能和作用部位在不同动物物种和组织中有所不同。在本研究中，研究了PGs（E1、E2、F2α、D2）对离体牛虹膜括约肌肌张力和神经介导收缩的影响。外源性应用这些PGs均未影响神经肌肉传递。相比之下，用吲哚美辛处理后，所有测试的PGs使肌肉收缩的程度比未用吲哚美辛时大得多，在这些条件下，PGs增强了对胆碱能神经刺激的反应。它们的半数有效剂量（ED50）分别为：前列腺素E1为（2.2±0.2）×10⁻⁷M，前列腺素E2为（6.7±0.3）×10⁻⁸M，前列腺素F2α为（7.3±0.4）×10⁻⁸M。前列腺素E1作用于神经和肌肉细胞。前列腺素E2主要通过神经发挥作用。在未用吲哚美辛时，前列腺素F2α的效力较低，而在用吲哚美辛处理后，前列腺素F2α主要对神经有更强的作用，对肌肉也有部分作用。高浓度的前列腺素D2具有接头前和接头后作用，同时伴有肌肉的微弱收缩。因此，接头前和接头后参与的程度彼此不同。单独应用这些PGs有可能掩盖了这类内源性物质的作用。为了理解和阐明PGs的作用部位和作用，用吲哚美辛预处理可能对虹膜肌肉有用。总之，PGs调节牛虹膜括约肌中的胆碱能活性，以及调节肌张力。
