Timolol plus acetazolamide: effect on formation of cerebrospinal fluid in cats and rats.
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 added to T after studying T alone, or when T is added to A after studying A alone. In contrast, in rats f-CSF is not influenced by T, either alone or when in combination with A. The rate in rats is reduced to 55% of control by treatments with A or A and T. Decrease in formation of cerebrospinal fluid by A occurs through inhibition of carbonic anhydrase, but the means whereby T (a known blocker of beta-adrenergic receptors) causes a reduction in f-CSF is not established; it is known that it does not inhibit carbonic anhydrase. Control of f-CSF by the sympathetic nervous system is discussed.
D000086:Acetazolamide / Q000494:pharmacology*; D000818:Animals; D002415:Cats; D002555:Cerebrospinal Fluid / Q000187:drug effects / Q000502:physiology*; D004347:Drug Interactions; D005260:Female; D007700:Kinetics; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013045:Species Specificity; D013999:Timolol / Q000494:pharmacology*
D013999:Timolol; D000086:Acetazolamide