INTRAOCULAR EFFECTS OF RUTHENIUM RED IN RESPONSES TO COMPOUND-48 COMPOUND-80 AND TOPICAL FORMALDEHYDE IN RABBIT/

We have previously shown the presence and localization of mast cells a nd the intraocular effects of compound 48/80 in the rabbit eye. In the present study we have evaluated the mechanism of action of compound 4 8/80 using ruthenium red as a blocker of sensory axon reflexes in the rabbit eye and by measuring the intraocular pressure (IOP), the pupil size, the blood pressure, the protein acid cAMP content in the aqueous humour. Topical neutral formaldehyde was used as a topical inducer of neuronally mediated response in a separate series of experiment. Intr acamerally-injected ruthenium red suppressed the compound 48/80-induce d elevation intraocular pressure and prevented miosis, while having li ttle if any effect on the breakdown of the blood-aqueous barrier and o n the increase in the cAMP concentration in aqueous humour. Ruthenium red also inhibited the irritative response in eyes treated with topica l 1% formaldehyde. As the blood-aqueous barrier in the rabbit is an ex tremely sensitive system higher doses of ruthenium red causes damage o f the barrier in the ruthenium red treated eyes. The results demonstra te that compound 48/80 not only has a mast cell degranulating effect b ut also a sensory nerve-stimulating effect.