Michel Martin C, Okutsu Hiroko, Noguchi Yukiko, Suzuki Masanori, Ohtake Akiyoshi, Yuyama Hironori, Yanai-Inamura Hiroko, Ukai Masashi, Watanabe Mai, Someya Akiyoshi, Sasamata Masao
Department of Pharmacology and Pharmacotherapy, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
Naunyn Schmiedebergs Arch Pharmacol. 2006 Feb;372(5):346-53. doi: 10.1007/s00210-006-0034-9. Epub 2006 Feb 18.
Alpha1-adrenoceptors mediate contraction of iris dilator smooth muscle and hence pupil dilatation. We compared the ability of i.v. bolus injections of alfuzosin, doxazosin, naftopidil, prazosin, tamsulosin and terazosin to antagonise phenylephrine-induced mydriasis relative to their potency for inhibiting phenylephrine-induced elevations of intraurethral pressure (IUP) in rabbits. Moreover, we compared the ability of these drugs to induce miosis in conscious rabbits in the absence of phenylephrine. All antagonists inhibited the effects of phenylephrine on pupil size and IUP, and the ratio of the respective ED50 values was close to unity in all cases. The doses required to induce statistically significant miosis in the absence of phenylephrine were 30- to 100-fold higher than those inhibiting phenylephrine-induced mydriasis for all antagonists, except for naftopidil. Moreover, the miotic effects of all alpha1-adrenoceptor antagonists were fully reversible within 8 h. We conclude that alfuzosin, doxazosin, naftopidil, prazosin, tamsulosin and terazosin inhibit phenylephrine-induced mydriasis in the same dose range as they inhibit elevations in IUP. Higher doses of all antagonists are required to induce miosis in the absence of an exogenous agonist, and such miosis is always reversible within hours.
α1肾上腺素能受体介导虹膜开大肌平滑肌收缩，从而导致瞳孔扩大。我们比较了静脉推注阿夫唑嗪、多沙唑嗪、萘哌地尔、哌唑嗪、坦索罗辛和特拉唑嗪拮抗去氧肾上腺素诱导的瞳孔散大的能力，以及它们抑制去氧肾上腺素诱导的兔尿道内压（IUP）升高的效力。此外，我们比较了这些药物在没有去氧肾上腺素的情况下使清醒兔瞳孔缩小的能力。所有拮抗剂均抑制去氧肾上腺素对瞳孔大小和IUP的作用，并且在所有情况下各自的半数有效剂量（ED50）值之比均接近1。除萘哌地尔外，在没有去氧肾上腺素的情况下诱导具有统计学意义的瞳孔缩小所需的剂量比抑制去氧肾上腺素诱导的瞳孔散大所需的剂量高30至100倍。此外，所有α1肾上腺素能受体拮抗剂的缩瞳作用在8小时内均可完全逆转。我们得出结论，阿夫唑嗪、多沙唑嗪、萘哌地尔、哌唑嗪、坦索罗辛和特拉唑嗪在抑制去氧肾上腺素诱导的瞳孔散大的剂量范围内，与它们抑制IUP升高的剂量范围相同。在没有外源性激动剂的情况下，需要更高剂量的所有拮抗剂来诱导瞳孔缩小，并且这种瞳孔缩小在数小时内总是可逆的。
