Pentobarbital: A short-acting barbiturate that is effective as a sedative and hypnotic (but not as an anti-anxiety) agent and is usually given orally. It is prescribed more frequently for sleep induction than for sedation but, like similar agents, may lose its effectiveness by the second week of continued administration. (From AMA Drug Evaluations Annual, 1994, p236)GABA Modulators: Substances that do not act as agonists or antagonists but do affect the GAMMA-AMINOBUTYRIC ACID receptor-ionophore complex. GABA-A receptors (RECEPTORS, GABA-A) appear to have at least three allosteric sites at which modulators act: a site at which BENZODIAZEPINES act by increasing the opening frequency of GAMMA-AMINOBUTYRIC ACID-activated chloride channels; a site at which BARBITURATES act to prolong the duration of channel opening; and a site at which some steroids may act. GENERAL ANESTHETICS probably act at least partly by potentiating GABAergic responses, but they are not included here.Hypnotics and Sedatives: Drugs used to induce drowsiness or sleep or to reduce psychological excitement or anxiety.Barbiturates: A class of chemicals derived from barbituric acid or thiobarbituric acid. Many of these are GABA MODULATORS used as HYPNOTICS AND SEDATIVES, as ANESTHETICS, or as ANTICONVULSANTS.Adjuvants, Anesthesia: Agents that are administered in association with anesthetics to increase effectiveness, improve delivery, or decrease required dosage.Anesthetics: Agents that are capable of inducing a total or partial loss of sensation, especially tactile sensation and pain. They may act to induce general ANESTHESIA, in which an unconscious state is achieved, or may act locally to induce numbness or lack of sensation at a targeted site.Chloralose: A derivative of CHLORAL HYDRATE that was used as a sedative but has been replaced by safer and more effective drugs. Its most common use is as a general anesthetic in animal experiments.Euthanasia, Animal: The killing of animals for reasons of mercy, to control disease transmission or maintain the health of animal populations, or for experimental purposes (ANIMAL EXPERIMENTATION).Receptors, GABA-A: Cell surface proteins which bind GAMMA-AMINOBUTYRIC ACID and contain an integral membrane chloride channel. Each receptor is assembled as a pentamer from a pool of at least 19 different possible subunits. The receptors belong to a superfamily that share a common CYSTEINE loop.Anesthesia: A state characterized by loss of feeling or sensation. This depression of nerve function is usually the result of pharmacologic action and is induced to allow performance of surgery or other painful procedures.Diazepam: A benzodiazepine with anticonvulsant, anxiolytic, sedative, muscle relaxant, and amnesic properties and a long duration of action. Its actions are mediated by enhancement of GAMMA-AMINOBUTYRIC ACID activity.Xylazine: An adrenergic alpha-2 agonist used as a sedative, analgesic and centrally acting muscle relaxant in VETERINARY MEDICINE.Ketamine: A cyclohexanone derivative used for induction of anesthesia. Its mechanism of action is not well understood, but ketamine can block NMDA receptors (RECEPTORS, N-METHYL-D-ASPARTATE) and may interact with sigma receptors.Thiopental: A barbiturate that is administered intravenously for the induction of general anesthesia or for the production of complete anesthesia of short duration.Isoflurane: A stable, non-explosive inhalation anesthetic, relatively free from significant side effects.Halothane: A nonflammable, halogenated, hydrocarbon anesthetic that provides relatively rapid induction with little or no excitement. Analgesia may not be adequate. NITROUS OXIDE is often given concomitantly. Because halothane may not produce sufficient muscle relaxation, supplemental neuromuscular blocking agents may be required. (From AMA Drug Evaluations Annual, 1994, p178)Urethane: Antineoplastic agent that is also used as a veterinary anesthetic. It has also been used as an intermediate in organic synthesis. Urethane is suspected to be a carcinogen.Dogs: The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)gamma-Aminobutyric Acid: The most common inhibitory neurotransmitter in the central nervous system.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Chloral Hydrate: A hypnotic and sedative used in the treatment of INSOMNIA.Anesthetics, General: Agents that induce various degrees of analgesia; depression of consciousness, circulation, and respiration; relaxation of skeletal muscle; reduction of reflex activity; and amnesia. There are two types of general anesthetics, inhalation and intravenous. With either type, the arterial concentration of drug required to induce anesthesia varies with the condition of the patient, the desired depth of anesthesia, and the concomitant use of other drugs. (From AMA Drug Evaluations Annual, 1994, p.173)Ether: A mobile, very volatile, highly flammable liquid used as an inhalation anesthetic and as a solvent for waxes, fats, oils, perfumes, alkaloids, and gums. It is mildly irritating to skin and mucous membranes.Dextroamphetamine: The d-form of AMPHETAMINE. It is a central nervous system stimulant and a sympathomimetic. It has also been used in the treatment of narcolepsy and of attention deficit disorders and hyperactivity in children. Dextroamphetamine has multiple mechanisms of action including blocking uptake of adrenergics and dopamine, stimulating release of monamines, and inhibiting monoamine oxidase. It is also a drug of abuse and a psychotomimetic.Chlordiazepoxide: An anxiolytic benzodiazepine derivative with anticonvulsant, sedative, and amnesic properties. It has also been used in the symptomatic treatment of alcohol withdrawal.Anesthesia, Intravenous: Process of administering an anesthetic through injection directly into the bloodstream.Secobarbital: A barbiturate that is used as a sedative. Secobarbital is reported to have no anti-anxiety activity.GABA-A Receptor Agonists: Endogenous compounds and drugs that bind to and activate GABA-A RECEPTORS.Reinforcement Schedule: A schedule prescribing when the subject is to be reinforced or rewarded in terms of temporal interval in psychological experiments. The schedule may be continuous or intermittent.Pregnanediones: Pregnane derivatives in which two side-chain methyl groups or two methylene groups in the ring skeleton (or a combination thereof) have been oxidized to keto groups.Etomidate: Imidazole derivative anesthetic and hypnotic with little effect on blood gases, ventilation, or the cardiovascular system. It has been proposed as an induction anesthetic.Columbidae: Family in the order COLUMBIFORMES, comprised of pigeons or doves. They are BIRDS with short legs, stout bodies, small heads, and slender bills. Some sources call the smaller species doves and the larger pigeons, but the names are interchangeable.Propofol: An intravenous anesthetic agent which has the advantage of a very rapid onset after infusion or bolus injection plus a very short recovery period of a couple of minutes. (From Smith and Reynard, Textbook of Pharmacology, 1992, 1st ed, p206). Propofol has been used as ANTICONVULSANTS and ANTIEMETICS.Picrotoxin: A noncompetitive antagonist at GABA-A receptors and thus a convulsant. Picrotoxin blocks the GAMMA-AMINOBUTYRIC ACID-activated chloride ionophore. Although it is most often used as a research tool, it has been used as a CNS stimulant and an antidote in poisoning by CNS depressants, especially the barbiturates.GABA Agonists: Endogenous compounds and drugs that bind to and activate GAMMA-AMINOBUTYRIC ACID receptors (RECEPTORS, GABA).Anesthetics, Inhalation: Gases or volatile liquids that vary in the rate at which they induce anesthesia; potency; the degree of circulation, respiratory, or neuromuscular depression they produce; and analgesic effects. Inhalation anesthetics have advantages over intravenous agents in that the depth of anesthesia can be changed rapidly by altering the inhaled concentration. Because of their rapid elimination, any postoperative respiratory depression is of relatively short duration. (From AMA Drug Evaluations Annual, 1994, p173)Triazolam: A short-acting benzodiazepine used in the treatment of insomnia. Some countries temporarily withdrew triazolam from the market because of concerns about adverse reactions, mostly psychological, associated with higher dose ranges. Its use at lower doses with appropriate care and labeling has been reaffirmed by the FDA and most other countries.Phencyclidine: A hallucinogen formerly used as a veterinary anesthetic, and briefly as a general anesthetic for humans. Phencyclidine is similar to KETAMINE in structure and in many of its effects. Like ketamine, it can produce a dissociative state. It exerts its pharmacological action through inhibition of NMDA receptors (RECEPTORS, N-METHYL-D-ASPARTATE). As a drug of abuse, it is known as PCP and Angel Dust.GABA-A Receptor Antagonists: Drugs that bind to but do not activate GABA-A RECEPTORS thereby blocking the actions of endogenous or exogenous GABA-A RECEPTOR AGONISTS.Aminobenzoates: Derivatives of BENZOIC ACID that contain one or more amino groups attached to the benzene ring structure. Included under this heading are a broad variety of acid forms, salts, esters, and amides that include the aminobenzoate structure.Ethoxzolamide: A carbonic anhydrase inhibitor used as diuretic and in glaucoma. It may cause hypokalemia.Anesthetics, Intravenous: Ultrashort-acting anesthetics that are used for induction. Loss of consciousness is rapid and induction is pleasant, but there is no muscle relaxation and reflexes frequently are not reduced adequately. Repeated administration results in accumulation and prolongs the recovery time. Since these agents have little if any analgesic activity, they are seldom used alone except in brief minor procedures. (From AMA Drug Evaluations Annual, 1994, p174)Meprobamate: A carbamate with hypnotic, sedative, and some muscle relaxant properties, although in therapeutic doses reduction of anxiety rather than a direct effect may be responsible for muscle relaxation. Meprobamate has been reported to have anticonvulsant actions against petit mal seizures, but not against grand mal seizures (which may be exacerbated). It is used in the treatment of ANXIETY DISORDERS, and also for the short-term management of INSOMNIA but has largely been superseded by the BENZODIAZEPINES. (From Martindale, The Extra Pharmacopoeia, 30th ed, p603)Anesthetics, Dissociative: Intravenous anesthetics that induce a state of sedation, immobility, amnesia, and marked analgesia. Subjects may experience a strong feeling of dissociation from the environment. The condition produced is similar to NEUROLEPTANALGESIA, but is brought about by the administration of a single drug. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed)Sorbose: A ketose sugar that is commonly used in the commercial synthesis of ASCORBIC ACID.Hexobarbital: A barbiturate that is effective as a hypnotic and sedative.Rats, Inbred Strains: Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Drug Interactions: The action of a drug that may affect the activity, metabolism, or toxicity of another drug.Muscimol: A neurotoxic isoxazole isolated from species of AMANITA. It is obtained by decarboxylation of IBOTENIC ACID. Muscimol is a potent agonist of GABA-A RECEPTORS and is used mainly as an experimental tool in animal and tissue studies.Diuretics, Osmotic: Compounds that increase urine volume by increasing the amount of osmotically active solute in the urine. Osmotic diuretics also increase the osmolarity of plasma.Discrimination Learning: Learning that is manifested in the ability to respond differentially to various stimuli.