The Central Ocular Hypotensive Effect of Brimonidine

Abstract

Abstract: : Purpose: To investigate the effect of brimonidine intracerebroventricula (ICV) treatment on intraocular pressure (IOP) in male pigmented rabbits. Methods: For ICV treatment, the guide cannula was inserted to lateral ventriculus following Fifkova’s brain map, 2 weeks before the injection. Ten uL brimonidine was injected (5 uL/min) ICV, or 20 uL brimonidine was administed to the lateral eye by topicaly. After the treatment, IOP was measured by pneumatonometer and pupil diameter (PD) was measured by ruler. Heart rate (HR) and mean arterial blood pressure (MABP) at metatarsus were also monitored by 0.01 topical administration. ARVO statement for the Use of Animals in Ophthalmic and Visual Research. Results: IOP of bilateral eyes were significantly decreased by 0.001% brimonidine ICV treatment group (15.30.6mmHg, p<0.01) or 0.05% brimonidine topical administration for lateral eye (10.60.6 mmHg, p<0.01), compared to saline treatment group (200.3mmHg ICV, 18.10.2mmHg topical administration). 0.01% brimonidine topical administration decreased IOP of treated eye (13.30.4mmhg,p<0.01) but did not decrease contralateral eye. The IOP decrease by ICV treatment was earlier to maximum than that by topical administration. PD, HR and MABP were not changed by 0.01topical administration of brimonidine. Conclusions: These results suggest that brimonidine might be mediated IOP not only by local effect, but also by the central nervous system in pigmented rabbit.

Keywords: intraocular pressure • pharmacology • animal model