title: Determination of halothane-induced sleeping time in the rat: effect of prior administration of centrally active drugs.
abstract: A method is described for the determination of halothane-induced sleeping time in the rat. 2 The sleeping time exhibited a diurnal variation which was due, at least in part, to a change in the sensitivity of the central nervous system (CNS) to the anaesthetic. 3 Tolerance to halothane did not develop in rats repeatedly exposed to the anaesthetic over a period of over 48 hours. 4 Repeated sleeping time determinations have been used to follow changes in the sensitivity of the CNS to the anaesthetic occurring with time. 5 A tolerance to halothane was induced by pretreatment of rats with doses of amylobarbitone, pentobarbitone or meprobamate sufficient to keep animals anaesthetized for approximately 12 hours. This tolerance was followed by a period of halothane-hypersensitivity. 6 Halothane-tolerant animals awakened with higher brain halothane concentrations and were also tolerant to intracerebroventricularly administered pentobarbitone. 7 Halothane-hypertensive rats awakened with lower brain halothane concentrations and were also hypersensitivity to intracerebroventricularly administered pentobarbitone. 8 The possibility that the induction of cross-tolerance to halothane may be indicative of a drug's potential to produce dependence is discussed.
mesh_terms: D000818:Animals; D001534:Bemegride / Q000494:pharmacology; D001923:Brain Chemistry / Q000187:drug effects; D002940:Circadian Rhythm; D004347:Drug Interactions; D005260:Female; D006221:Halothane / Q000032:analysis / Q000494:pharmacology*; D007276:Injections, Intraventricular; D008099:Liver / Q000032:analysis; D010424:Pentobarbital / Q000008:administration & dosage / Q000032:analysis; D010634:Phenobarbital / Q000494:pharmacology; D011335:Proadifen / Q000494:pharmacology; D051381:Rats; D012640:Seizures / Q000139:chemically induced; D012890:Sleep / Q000187:drug effects*; D013997:Time Factors
chemical_list: D001534:Bemegride; D011335:Proadifen; D010424:Pentobarbital; D006221:Halothane; D010634:Phenobarbital