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Abstract #6359 Published in IGR 3-2
Reliable measurement of mouse intraocular pressure by a servo-null micropipette system
Avila MY; Carré DA; Stone RA; Civan MMInvestigative Ophthalmology and Visual Science 2001; 42: 1841-1846
PURPOSE: To develop a reliable technique for measuring intraocular pressure (IOP) in the mouse. METHODS: An electrophysiological approach - the servo-null micropipette system (SNMS) - for measuring hydrostatic pressure was adapted for the mouse eye. Fine-tipped (5 μm in diameter) micropipettes were advanced across the cornea with a piezo-electric micromanipulator, and the IOP was continuously monitored for up to 46 minutes. RESULTS: The micropipette tip was visualized in the anterior chamber. With SNMS, the IOP of black Swiss outbred mice under ketamine anesthesia was 17.8 ± 0.4 mmHg, higher than values previously estimated in inbred mouse strains by a larger bore microneedle manometric technique. After withdrawal of the micropipette, a second penetration led to a similar level of IOP. Hypotonic solutions increased and hypertonic solutions decreased IOP. Drugs that decrease inflow (acetazolamide, timolol) or increase outflow (pilocarpine, latanoprost) facility in primates and humans lowered steady-state IOP in the mouse. The transient initial increase in IOP produced by pilocarpine, reported in other animals, was also observed in the mouse. Xylazine-ketamine anesthesia lowered IOP substantially in comparison with systemic anesthesia with either ketamine or tribomoethanol alone. CONCLUSIONS: SNMS is the first reliable, reproducible method for measuring mouse IOP. Mouse IOP is sensitive, not only to drugs known to reduce aqueous humor inflow, but also to drugs that increase aqueous humor outflow facility in the eyes of primates and humans. The development of SNMS is an enabling step in the use of the mouse for glaucoma research, including molecular genetics, molecular pharmacology, and the search for novel antiglaucoma drugs.
Dr M.M. Civan, Department of Physiology, University of Pennsylvania, Richards Building, Philadelphia, PA 19104-6085, USA
Classification:
5 Experimental glaucoma; animal models
6.1 Intraocular pressure measurement; factors affecting IOP (Part of: 6 Clinical examination methods)
