Cerebrospinal fluid formation in rats and cats during treatment with timolol.
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.
D000818:Animals; D001082:Aqueous Humor / Q000187:drug effects; D002415:Cats; D002555:Cerebrospinal Fluid / Q000187:drug effects* / Q000502:physiology; D005260:Female; D007275:Injections, Intravenous; D007276:Injections, Intraventricular; D008297:Male; D011412:Propanolamines / Q000494:pharmacology*; D051381:Rats; D013997:Time Factors; D013999:Timolol / Q000008:administration & dosage / Q000494:pharmacology*
D011412:Propanolamines; D013999:Timolol