Effect of ouabain on cerebrospinal fluid formation after carbonic anhydrase inhibition

The effect of ventriculo-cisternal perfusion of ouabain was determined on CSF production after inhibition of carbonic anhydrase by benzolamide in cats. An additional decrease in CSF formation was observed by combination of i.v. benzolamide and intraventricular ouabain. However, the effect of the combined drugs was less than the sum of the effects of the drugs given individually. It is concluded that the reduction of the CSF production by ouabain is probably partly due to its effect on Na-K exchange (through inhibition of Na-K-activated ATPase) and partly due to its effects on Na+ transport coupled to anion transport mediated by carbonic anhydrase.