Vascular effect of various antiglaucoma agent on ciliary artery smooth muscle cells.

虽然人们普遍认为降低眼压(IOP)对治疗正常眼压性青光眼(NTG)很重要，但增加眼部血管灌注量也被认为是重要的。本研究的目的是从药理上阐明各种化合物治疗青光眼的血管扩张机制。我们观察了β-受体拮抗剂或前列腺素相关化合物对体外培养的兔和大鼠睫状动脉的作用。据报道，这些化合物除了降低眼压外，还对眼循环有影响。倍他洛尔的作用类似于钙拮抗剂，呈剂量依赖性地松弛兔纤毛动脉。尼普拉地洛是另一种用于治疗青光眼的BE-TA拮抗剂，作为NO供体，它也可以松弛兔的睫状动脉。左旋布洛尔还通过改变细胞内钙敏感性来松弛肌肉。这些Be-Ta拮抗剂均通过不同的机制松弛兔睫状动脉，均不是Be-Ta受体拮抗作用。乌诺前列酮，一种前列腺素相关的化合物，也用于治疗青光眼，放松这块肌肉。Unoprostone的肌松作用机制可能是通过抑制Ca~(2+)内流，可能是通过容积性Ca~(2+)通道实现的。另一种与前列腺素相关的化合物拉坦前列素具有较强的降眼压能力，对兔睫状动脉也有松弛作用，但作用弱于乌索前列酮。这些结果表明，许多抗冰冻剂通过不同的机制松弛血管平滑肌，这与降低眼压的机制不同。这些发现可能为开发改善眼循环的新药提供有用的信息。

Though it is generally accepted that decreasing intraocular pressure (IOP) is important to treat normal tension glaucoma (NTG), increasing ocular vascular perfusion is also considered to be important. The purpose of this study is to clarify the vasodilatory mechanism of various compound used for treatment of glaucoma, pharmacologically. We have investigated the effect of beta antagonists or prostaglandin related compounds on isolated rabbit and rat ciliary artery in vitro. These compound were reported to have effect on ocular circulation in addition to decrease IOP. Betaxolol dose-dependently relax rabbit ciliaryn artery by action similar to Ca antagonists. NIpradilol, another be-ta antagonist used for treatment of glaucoma, also relax rabbit ciliary artery as NO-donor. Levobumolol also relax this muscle by changing intracellular calcium sensitivity. All these be-ta antagonists relax rabbit ciliary artery by different mechanisms all which are not be-ta receptor antagonistic action. Unoprostone, a prostaglandin related compound also used for treatment of glaucoma, relax this muscle. The mechanism of muscle relaxation by unoprostone may be mediated by inhibition of Ca^<2+> entry, possibly through capacitative Ca^<2+> channels. Latanoprost, another prostaglandin related compound and stronger capability of reducing IOP also relax rabbit ciliary artery but the action is weaker than unoprostone. These results indicate that many antiglacoma agents relax vascular smooth muscle by various mechanisms which is different from the mechanisms of reducing IOP. These findings may provide useful information for developing new drugs for improving ocular circula