Cerebrospinal fluid formation in rats and cats during treatment with timolol

• Published in: Canadian journal of physiology and pharmacology Vol. 60; no. 8; p. 1138
• Main Authors: Vogh, B P, Godman, D R
• Format: Journal Article
• Language: English
• Published: Canada 01-08-1982
• Subjects: Animals; Aqueous Humor - drug effects; Cats; Cerebrospinal Fluid - drug effects; Cerebrospinal Fluid - physiology; Female; Injections, Intravenous; Injections, Intraventricular; Male; Propanolamines - pharmacology; Rats; Time Factors; Timolol - administration & dosage; Timolol - pharmacology
• ISSN: 0008-4212
• DOI: 10.1139/y82-164

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 change from control rates occurred. In the cats there appeared to be no effect of intraventricular timolol; however, a significant decrease of approximately 25% in the mean flow rate was seen after 40 min when drug was given i.v. at either dose level. A time study showed that no further decrease occurred within 5 h and that the observed decrease continued for at least 3 h. These findings are of interest in view of the ability of topical, intraocular, and i.v. timolol to reduce aqueous humor formation rate.