title: Osmotic minipumps for administration of barbital to mice: demonstration of functional tolerance and physical dependence.
abstract: Sodium barbital was administered to mice at a constant rate by miniature osmotic pumps implanted subcutaneously. Each pump delivered approximately 0.25 mg/hr. With two pumps per mouse, blood barbital levels of 20 to 30 microgram/ml could be maintained for various periods. Barbital was assayed by gas chromatography. Functional tolerance was shown by a significant decrease in sleep time after a challenge dose of barbital administered 24 hours after withdrawal. Physical dependence was demonstrated by withdrawal hyperexcitability as measured either with pentylenetetrazol or by convulsions elicited by handling.
mesh_terms: D000818:Animals; D001462:Barbital / Q000008:administration & dosage* / Q000097:blood / Q000494:pharmacology; D001463:Barbiturates / Q000008:administration & dosage*; D004361:Drug Tolerance; D006801:Humans; D008297:Male; D051379:Mice; D012640:Seizures / Q000209:etiology; D013375:Substance Withdrawal Syndrome / Q000150:complications; D019966:Substance-Related Disorders / Q000209:etiology*; D013997:Time Factors
chemical_list: D001463:Barbiturates; D001462:Barbital