advertisement
Abstract #9944 Published in IGR 5-3
4-Aminopyridine transiently increases intraocular pressure in rabbits
Socci RR; Chu E; Bayorh MA; Chu TCPharmacology 2003; 69: 108-114
The purpose of this study was to determine the mechanisms of action involved in the ocular hypertension induced by 4-aminopyridine (4-AP), a voltage-dependent potassium (K+) channel blocker, in rabbits. Topical application of 4-AP elevated intraocular pressure (IOP). This action caused increases in the aqueous flow rate as well as aqueous levels of protein and norepinephrine. In isolated iris-ciliary body preparations, 4-AP (0.01, 0.1, 1 mmol/l) caused dose-related increases in field-stimulated norepinephrine release by 43, 222 and 243%, respectively. Taken together, the IOP-elevating effect evoked by 4-AP was associated with enhancement of aqueous norepinephrine levels and norepinephrine release from sympathetic nerves of the iris-ciliary body. These results demonstrate that the 4-AP-sensitive K+ channels in sympathetic nerves and the ciliary epithelium are the potential sites of action of the 4-AP-induced ocular hypertension.
Dr. T.C. Chu, Department of Pharmacology and Toxicology, Morehouse School of Medicine, 720 Westview Drive, Atlanta, GA 30310-1495, USA
Classification:
11.14 Investigational drugs; pharmacological experiments (Part of: 11 Medical treatment)
