Fanciullacci M, Sicuteri R, Alessandri M, Geppetti P
Institute of Internal Medicine and Therapeutics IV, University of Florence, Italy.
Clin Pharmacol Ther. 1995 Mar;57(3):349-55. doi: 10.1016/0009-9236(95)90161-2.
Drugs that act on the serotoninergic system have been shown to influence the pupil size. However, the 5-hydroxytryptamine (5-HT) receptor type or subtype that affects pupil diameter has not been defined in humans. With a placebo-controlled, double-blind randomized design, we investigated in healthy volunteers the effect on pupil size of buspirone and sumatriptan, which mainly act on 5-HT1A- and the 5-HT1-like receptors, respectively.
The pupil area was measured by means of a videopupillometer before and after a single oral administration of placebo or of three different doses of active drugs. Heart rate and arterial blood pressure were recorded after pupil area measurement.
Buspirone (5, 10, and 20 mg) caused a dose-dependent miosis. Sumatriptan (50, 100, and 200 mg) did not affect the pupil size. Twenty milligrams of buspirone reduced the mydriasis induced by pretreatment with homatropine eyedrops. A 20 mg dose of buspirone reduced blood pressure without change in heart rate, whereas buspirone, at doses lower than 20 mg, and sumatriptan did not affect heart rate and blood pressure.
This study suggests that buspirone, but not sumatriptan, the selective agonist of 5-HT1-like receptors, causes miosis in humans by activation of 5-HT1A receptors, possibly located in the central nervous system where they inhibit iris sympathetic pathways. Measurement of pupil size seems to provide a valuable and sensitive index of 5-HT1A receptor function in humans.
作用于血清素能系统的药物已被证明会影响瞳孔大小。然而，在人类中，影响瞳孔直径的5-羟色胺（5-HT）受体类型或亚型尚未明确。通过安慰剂对照、双盲随机设计，我们在健康志愿者中研究了主要分别作用于5-HT1A受体和5-HT1类受体的丁螺环酮和舒马曲坦对瞳孔大小的影响。
在单次口服安慰剂或三种不同剂量的活性药物前后，使用视频瞳孔计测量瞳孔面积。在测量瞳孔面积后记录心率和动脉血压。
丁螺环酮（5、10和20毫克）引起剂量依赖性的瞳孔缩小。舒马曲坦（50、100和200毫克）不影响瞳孔大小。20毫克丁螺环酮可减轻用后马托品滴眼液预处理引起的散瞳。20毫克剂量的丁螺环酮可降低血压而心率不变，而低于20毫克剂量的丁螺环酮和舒马曲坦不影响心率和血压。
本研究表明，5-HT1类受体的选择性激动剂丁螺环酮而非舒马曲坦，通过激活可能位于中枢神经系统的5-HT1A受体导致人类瞳孔缩小，在中枢神经系统中它们抑制虹膜交感神经通路。瞳孔大小的测量似乎为人类5-HT1A受体功能提供了一个有价值且敏感的指标。
