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PURPOSE To determine whether the well-known effect of timolol in reducing ocular pressure and aqueous humor (AH) flow is a function of reduced Na+ movement from plasma to aqueous. Previously, the authors have shown this to be the case for carbonic anhydrase inhibitors. METHODS The rate of appearance of 22Na in rabbit posterior aqueous was measured 1 to 3(More)
Our earlier report that perfusion of Al and Ga salts through rat brain ventricles abolished cerebrospinal fluid (CSF) production is incorrect. We now realize there are three conditions which, when simultaneously present, will give a false reading of the events taking place. These are: metal salts, low pH with subsequent rise in pH during perfusion and use(More)
To achieve selective inhibition of cytosolic and membrane-bound carbonic anhydrase (CA II and CA IV, respectively), we synthesized a polymer of molecular weight 3500 from polyoxyethylene bis acetic acid and aminobenzolamide. The new compound, designated F (for Florida) 3500, is stable, water soluble and nontoxic. It is excreted largely unchanged by(More)
In a system for ventriculocisternal perfusion of the choroid plexus, the rate of formation of new cerebrospinal fluid was measured by changes in dilution of an impermeant dye in the perfusate. Norepinephrine added to the perfusate decreased formation of cerebrospinal fluid in rats as was previously demonstrated in rabbits. The dose-response relationship for(More)
Administration iv of 50 mg X kg-1 acetazolamide (A) and 3 mg X kg-1 timolol (T) causes the formation of cerebrospinal fluid (f-CSF) to be reduced to 43.7% of the control rate compared with a reduction to 82.5% of control by T alone and to 52.6% of control by A alone. The effect of combined drugs is the same when A is combined with T initially, when A is(More)
A simple technique for rapid determination of the flow of aqueous humor (AH) in rabbits is described. Data from control eyes and eyes treated with known inhibitors of aqueous humor production are presented as evidence of the suitability of the technique for comparing the influence of other drugs on aqueous flow. The flow measurement depends on marker(More)
The influence of timolol upon cerebrospinal fluid formation rate has been examined in rats by the measurement of 22Na+ entry into this fluid after 10, 100, or 1000 micrograms x kg-1 i.v. and in cats by the dye-dilution measurement of new fluid formation after 30, or 3000 microgram x kg-1 i.v., or 250 micrograms x mL-1 in ventricular perfusate. In rats no(More)
Inhibitors of angiotensin converting enzyme (ACE) (1) and of carbonic anhydrase (CA) (2,3) decrease intraocular pressure (IOP) in conscious rabbits. We asked whether ACE inhibition decreases IOP through effects on CA-dependent flow of aqueous humor (AH) and whether ACE inhibitors decrease other CA-dependent secretions. We show in anesthetized rabbits (a)(More)
AlCl3 or GaCl3 was added to artificial cerebrospinal fluid and perfused through the cerebral ventricles of the rat. Depending on the metal and its concentration (1-10 mM) the pH of the perfusate ranged from 7.2 to 3.5. At 10 mM metal chloride, yielding pH 4.7 (Al) or 3.5 (Ga), formation of cerebrospinal fluid was suppressed 100%. The effect was reversed as(More)
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