Liu J H, Dacus A C
Eye Research Institute of Retina Foundation, Boston, MA 02114.
Invest Ophthalmol Vis Sci. 1990 Jul;31(7):1332-8.
Intracerebroventricular (ICV) injection of carbachol into the third ventricle of conscious rabbits increased pupil size and intraocular pressure (IOP). A significant increase of pupil size by 0.6-1.3 mm for 60-90 min was observed with the dose of 1 microgram and an increase of IOP by 1.1-1.9 mmHg for 15-60 min was observed with doses over 10 ng. These responses were due to central cholinergic stimulation; mydriasis was eliminated by ICV injection of atropine and the elevation of IOP was significantly reduced by ICV injections of atropine and hexamethonium. Transection of the cervical sympathetic trunk eliminated the mydriasis. The efferent pathway for the mydriasis is via the cervical sympathetic nerve. The elevation of IOP was significantly reduced but not eliminated in the decentralized eye. Plasma epinephrine (Epi) and norepinephrine (NE) increased at 30 min after the ICV injection of 1 microgram carbachol. It is hypothesized that the elevation of IOP is due mainly to the stimulation of ocular sympathetic nerves and the increase of circulating catecholamines. Topical treatment of 0.01% timolol significantly reduced the IOP elevation, indicating the involvement of ocular beta-adrenergic mechanism in the elevation of IOP.
向清醒家兔的第三脑室脑室内（ICV）注射卡巴胆碱可使瞳孔扩大和眼压（IOP）升高。注射1微克剂量时，观察到瞳孔大小在60 - 90分钟内显著增加0.6 - 1.3毫米；注射剂量超过10纳克时，观察到眼压在15 - 60分钟内升高1.1 - 1.9毫米汞柱。这些反应是由于中枢胆碱能刺激所致；通过ICV注射阿托品可消除瞳孔散大，而ICV注射阿托品和六甲铵可显著降低眼压升高。切断颈交感干可消除瞳孔散大。瞳孔散大的传出途径是通过颈交感神经。在去神经支配的眼睛中，眼压升高虽显著降低但未消除。ICV注射1微克卡巴胆碱后30分钟，血浆肾上腺素（Epi）和去甲肾上腺素（NE）增加。据推测，眼压升高主要是由于眼交感神经受到刺激以及循环中儿茶酚胺增加所致。局部应用0.01%噻吗洛尔可显著降低眼压升高，表明眼β - 肾上腺素能机制参与了眼压升高过程。
