A study of the duration of acute tolerance induced with hexobarbital in male rats.
Male rats were infused i.v. with hexobarbital to obtain a burst suppression of 1 s or more in the EEG (SS). At SS the rats were killed and the concentration of hexobarbital was determined by HPLC in three parts of the brain. Acute tolerance (induced by a 1-h exposure at the SS level) was recorded as an approximately 20% increase in brain concentrations of hexobarbital at the last SS during the exposure when compared with concentrations recorded at the first SS in the controls. Increased brain concentrations (approximately 8%) at SS were recorded 24 h after induction of acute tolerance. After 48 h the increase was uncertain. Thus, acute tolerance to hexobarbital could have cumulative properties if new exposures are imposed after 24 h.
Wahlström
G
G
Department of Pharmacology, University of Umeå, Sweden.
D000818:Animals; D001921:Brain / Q000378:metabolism; D004361:Drug Tolerance; D004569:Electroencephalography / Q000187:drug effects; D006591:Hexobarbital / Q000493:pharmacokinetics / Q000494:pharmacology*; D006993:Hypnotics and Sedatives / Q000493:pharmacokinetics / Q000494:pharmacology*; D008297:Male; D051381:Rats; D013056:Spectrophotometry, Ultraviolet; D013997:Time Factors; D014018:Tissue Distribution
D006993:Hypnotics and Sedatives; D006591:Hexobarbital