Wilkie D A, Latimer C A
Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Ohio State University, Columbus 43210.
Am J Vet Res. 1991 Mar;52(3):436-40.
Effects of topical administration of a single dose of timolol maleate, a nonselective beta-adrenergic blocking agent, on intraocular pressure (IOP) and pupil diameter were evaluated in the normotensive eyes of 10 clinically normal cats over 12 hours. Mean (+/- SEM) normal IOP was 17.1 (+/- 1.1) mm of Hg and diurnal fluctuation was observed, with the highest IOP seen in the evening. Mean (+/- SEM) normal pupil diameter was 10.1 (+/- 0.5) mm. Topical treatment with 0.5% timolol resulted in reduction of IOP in treated and nontreated eyes. This effect was time-dependent and was first observed at 6 hours after treatment. Mean reduction of IOP was 22.3% in the treated eye and 16.3% in the nontreated eye. The treated eye had reduced pupil diameter at 30 minutes after treatment, and miosis persisted throughout the 12 hours of the study. Mean reduction of pupil diameter was 38.7%. A contralateral effect on pupil diameter was not seen in the nontreated eye. Topical administration of timolol maleate results in a reduction of IOP in treated and contralateral eyes, which supports the use of timolol for treatment of glaucoma in cats. In addition, the treated eye becomes miotic. This effect may indicate beta-adrenergic inhibition or alpha-adrenergic activation of the iris sphincter muscle. beta-Adrenergic blockade would then result in miosis.
在10只临床正常猫的正常眼压眼中，评估了单剂量局部应用马来酸噻吗洛尔（一种非选择性β-肾上腺素能阻滞剂）对眼压（IOP）和瞳孔直径的影响，观察时间为12小时。平均（±标准误）正常眼压为17.1（±1.1）mmHg，观察到有昼夜波动，傍晚时眼压最高。平均（±标准误）正常瞳孔直径为10.1（±0.5）mm。用0.5%噻吗洛尔局部治疗导致治疗眼和未治疗眼的眼压均降低。这种作用具有时间依赖性，在治疗后6小时首次观察到。治疗眼的眼压平均降低22.3%，未治疗眼降低16.3%。治疗眼在治疗后30分钟瞳孔直径减小，在整个12小时的研究过程中瞳孔缩小持续存在。瞳孔直径平均减小38.7%。未治疗眼未观察到对瞳孔直径的对侧效应。局部应用马来酸噻吗洛尔可使治疗眼和对侧眼的眼压降低，这支持将噻吗洛尔用于猫青光眼的治疗。此外，治疗眼会出现瞳孔缩小。这种效应可能表明虹膜括约肌的β-肾上腺素能抑制或α-肾上腺素能激活。β-肾上腺素能阻断随后会导致瞳孔缩小。
