The effect of acetazolamide on the movement of sodium into the posterior chamber of the dog eye.

The rate of appearance (entry) of 22Na into the posterior chamber of the eye was determined in eight dogs under control conditions and again after pretreatment with acetazolamide, 50 mg/kg i.v. In comparison with the paired controls, pretreatment with acetazolamide decreased the average rate of entry of 22Na by 29% during the first 3 minutes after the intravenous administration of a tracer dose of the isotope. In separate experiments, the volumes of the chambers of the dog eye and the rate of aqueous humor formation were determined for the purpose of calculating nascent fluid ion concentrations. Comparisons of sodium data with the previously reported anion data are made. Results support the suggestion that reduction of intraocular pressure caused by acetazolamide is partially, if not wholly, the result of the action of the drug to reduce the secretion of aqueous humor.