title: Pentobarbital distribution in discrete brain areas of tolerant and nontolerant mice.
abstract: Uptake and distribution of pentobarbital in tolerant and nontolerant mice were studied. Mice were implanted with pentobarbital or placebo pellets s.c. 3 days prior to the injection of 60 mg/kg sodium pentobarbital i.p. One group of animals was sacrificed when they first awakened. Whole brain, five discrete brain areas, and plasma were assayed for pentobarbital by gas chromatography. In a second group, time studies were performed on brain sections and plasma. In tolerant vs nontolerant animals, sleeping time was markedly decreased (10-20 vs 50-70 min); whole brain, brain sections, and plasma levels on awakening were not significantly different; linear and exponential curves of pentobarbital levels vs time showed an increase in slope (-1.05 vs-0.40) and a decrease in T 1/2 (10.2 VS 35.7 min). These findings suggest that the tolerance development to pentobarbital in the central nervous system is due to functional mechanism rather than brain dispositional mechanism.
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D004343:Drug Implants; D004361:Drug Tolerance; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D010424:Pentobarbital / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D012890:Sleep / Q000187:drug effects; D013997:Time Factors
chemical_list: D004343:Drug Implants; D010424:Pentobarbital