Hasegawa N, Imaizumi Y, Watanabe M
Jpn J Pharmacol. 1987 Feb;43(2):143-51. doi: 10.1254/jjp.43.143.
Supersensitivity in chronically sympathectomized smooth muscle has long been studied, but little is known about chronically parasympathectomized smooth muscles. Iris is one of the few smooth muscle organs which can be parasympathetically denervated. We used rats because the denervation supersensitivity in the vas deferens has extensively been studied in this species. The rat was unilaterally ciliary-ganglionectomized. After 1-13 days, strips of the iris sphincter muscle obtained from denervated eye were tested for the sensitivity to acetylcholine (ACh), 5-hydroxytryptamine (5-HT) and K+. A significant increase in sensitivity to ACh and 5-HT was recognized as early as 1 day after the operation, and the sensitivity reached a maximum after 5-6 days, when ED50 values of ACh and 5-HT were reduced to approximately 1/28 and 1/4, respectively. The sensitivity to K+ was unaffected. When the sensitivity reached the maximum, the maximum responses to ACh, 5-HT and K+ were increased by 50%, 140% and 50%, respectively. The shift of the dose-response curve for bethanechol (BeCh) after denervation was comparable to that for ACh. Physostigmine shifted the curve for ACh, but did not shift that for BeCh either before or after denervation. Specific binding of 3H-quinuclidinyl benzylate tended to decrease after denervation, but the change was statistically not significant. These results indicate that the parasympathetic denervation supersensitivity in the rat iris sphincter involves a non-specific component, in addition to one specific to ACh and BeCh. The specific component seems to involve postsynaptic mechanisms.
长期以来，人们一直在研究慢性交感神经切除的平滑肌的超敏反应，但对于慢性副交感神经切除的平滑肌却知之甚少。虹膜是少数几种可以进行副交感神经去神经支配的平滑肌器官之一。我们使用大鼠，因为在这个物种中已经广泛研究了输精管的去神经超敏反应。将大鼠单侧睫状神经节切除。术后1 - 13天，对取自去神经眼的虹膜括约肌条进行乙酰胆碱（ACh）、5 - 羟色胺（5 - HT）和钾离子（K⁺）敏感性测试。早在术后1天就观察到对ACh和5 - HT的敏感性显著增加，5 - 6天后敏感性达到最大值，此时ACh和5 - HT的半数有效剂量（ED50）值分别降至约1/28和1/4。对K⁺的敏感性未受影响。当敏感性达到最大值时，对ACh、5 - HT和K⁺的最大反应分别增加了50%、140%和50%。去神经后氨甲酰甲胆碱（BeCh）的剂量 - 反应曲线的移位与ACh的相似。毒扁豆碱使ACh的曲线移位，但在去神经前后均未使BeCh的曲线移位。去神经后3H - 喹核醇基苯甲酸酯的特异性结合趋于降低，但变化在统计学上不显著。这些结果表明，大鼠虹膜括约肌的副交感神经去神经超敏反应除了涉及对ACh和BeCh特异的成分外，还涉及非特异性成分。特异性成分似乎涉及突触后机制。
