Scopolamine Hydrobromide: An alkaloid from SOLANACEAE, especially DATURA and SCOPOLIA. Scopolamine and its quaternary derivatives act as antimuscarinics like ATROPINE, but may have more central nervous system effects. Among the many uses are as an anesthetic premedication, in URINARY INCONTINENCE, in MOTION SICKNESS, as an antispasmodic, and as a mydriatic and cycloplegic.Scopolamine Derivatives: Analogs or derivatives of scopolamine.Muscarinic Antagonists: Drugs that bind to but do not activate MUSCARINIC RECEPTORS, thereby blocking the actions of endogenous ACETYLCHOLINE or exogenous agonists. Muscarinic antagonists have widespread effects including actions on the iris and ciliary muscle of the eye, the heart and blood vessels, secretions of the respiratory tract, GI system, and salivary glands, GI motility, urinary bladder tone, and the central nervous system.Cholinergic Antagonists: Drugs that bind to but do not activate CHOLINERGIC RECEPTORS, thereby blocking the actions of ACETYLCHOLINE or cholinergic agonists.N-Methylscopolamine: A muscarinic antagonist used to study binding characteristics of muscarinic cholinergic receptors.Butylscopolammonium Bromide: Antimuscarinic quaternary ammonium derivative of scopolamine used to treat cramps in gastrointestinal, urinary, uterine, and biliary tracts, and to facilitate radiologic visualization of the gastrointestinal tract.Receptors, Muscarinic: One of the two major classes of cholinergic receptors. Muscarinic receptors were originally defined by their preference for MUSCARINE over NICOTINE. There are several subtypes (usually M1, M2, M3....) that are characterized by their cellular actions, pharmacology, and molecular biology.Dihydroalprenolol: Hydrogenated alprenolol derivative where the extra hydrogens are often tritiated. This radiolabeled form of ALPRENOLOL, a beta-adrenergic blocker, is used to label the beta-adrenergic receptor for isolation and study.Physostigmine: A cholinesterase inhibitor that is rapidly absorbed through membranes. It can be applied topically to the conjunctiva. It also can cross the blood-brain barrier and is used when central nervous system effects are desired, as in the treatment of severe anticholinergic toxicity.Sialorrhea: Increased salivary flow.Administration, Cutaneous: The application of suitable drug dosage forms to the skin for either local or systemic effects.Avoidance Learning: A response to a cue that is instrumental in avoiding a noxious experience.Tacrine: A cholinesterase inhibitor that crosses the blood-brain barrier. Tacrine has been used to counter the effects of muscle relaxants, as a respiratory stimulant, and in the treatment of Alzheimer's disease and other central nervous system disorders.Cholinergic Agents: Any drug used for its actions on cholinergic systems. Included here are agonists and antagonists, drugs that affect the life cycle of ACETYLCHOLINE, and drugs that affect the survival of cholinergic neurons. The term cholinergic agents is sometimes still used in the narrower sense of MUSCARINIC AGONISTS, although most modern texts discourage that usage.Oxotremorine: A non-hydrolyzed muscarinic agonist used as a research tool.Atropa belladonna: A plant species of the genus ATROPA, family SOLANACEAE that contains ATROPINE; SCOPOLAMINE; BELLADONNA ALKALOIDS and other SOLANACEOUS ALKALOIDS. Some species in this genus are called deadly nightshade which is also a common name for SOLANUM.Chorioamnionitis: INFLAMMATION of the placental membranes (CHORION; AMNION) and connected tissues such as fetal BLOOD VESSELS and UMBILICAL CORD. It is often associated with intrauterine ascending infections during PREGNANCY.Chloramphenicol O-Acetyltransferase: An enzyme that catalyzes the acetylation of chloramphenicol to yield chloramphenicol 3-acetate. Since chloramphenicol 3-acetate does not bind to bacterial ribosomes and is not an inhibitor of peptidyltransferase, the enzyme is responsible for the naturally occurring chloramphenicol resistance in bacteria. The enzyme, for which variants are known, is found in both gram-negative and gram-positive bacteria. EC Inhibitors: Drugs that inhibit cholinesterases. The neurotransmitter ACETYLCHOLINE is rapidly hydrolyzed, and thereby inactivated, by cholinesterases. When cholinesterases are inhibited, the action of endogenously released acetylcholine at cholinergic synapses is potentiated. Cholinesterase inhibitors are widely used clinically for their potentiation of cholinergic inputs to the gastrointestinal tract and urinary bladder, the eye, and skeletal muscles; they are also used for their effects on the heart and the central nervous system.Cholinergic Fibers: Nerve fibers liberating acetylcholine at the synapse after an impulse.Amnesia: Pathologic partial or complete loss of the ability to recall past experiences (AMNESIA, RETROGRADE) or to form new memories (AMNESIA, ANTEROGRADE). This condition may be of organic or psychologic origin. Organic forms of amnesia are usually associated with dysfunction of the DIENCEPHALON or HIPPOCAMPUS. (From Adams et al., Principles of Neurology, 6th ed, pp426-7)Memory: Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory.Competitive Bidding: Pricing statements presented by more than one party for the purpose of securing a contract.Mecamylamine: A nicotinic antagonist that is well absorbed from the gastrointestinal tract and crosses the blood-brain barrier. Mecamylamine has been used as a ganglionic blocker in treating hypertension, but, like most ganglionic blockers, is more often used now as a research tool.Pirenzepine: An antimuscarinic agent that inhibits gastric secretion at lower doses than are required to affect gastrointestinal motility, salivary, central nervous system, cardiovascular, ocular, and urinary function. It promotes the healing of duodenal ulcers and due to its cytoprotective action is beneficial in the prevention of duodenal ulcer recurrence. It also potentiates the effect of other antiulcer agents such as CIMETIDINE and RANITIDINE. It is generally well tolerated by patients.Acetylcholine: A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites 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.Tropanes: N-methyl-8-azabicyclo[3.2.1]octanes best known for the ones found in PLANTS.Bile Duct Neoplasms: Tumors or cancer of the BILE DUCTS.Solanaceous Alkaloids: Alkaloids, mainly tropanes, elaborated by plants of the family Solanaceae, including Atropa, Hyoscyamus, Mandragora, Nicotiana, Solanum, etc. Some act as cholinergic antagonists; most are very toxic; many are used medicinally.Muscarinic Agonists: Drugs that bind to and activate muscarinic cholinergic receptors (RECEPTORS, MUSCARINIC). Muscarinic agonists are most commonly used when it is desirable to increase smooth muscle tone, especially in the GI tract, urinary bladder and the eye. They may also be used to reduce heart rate.Adjuvants, Anesthesia: Agents that are administered in association with anesthetics to increase effectiveness, improve delivery, or decrease required dosage.Lorazepam: A benzodiazepine used as an anti-anxiety agent with few side effects. It also has hypnotic, anticonvulsant, and considerable sedative properties and has been proposed as a preanesthetic agent.Atropine: An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.Molecular Structure: The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.Structure-Activity Relationship: The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.Artemisinins: A group of SESQUITERPENES and their analogs that contain a peroxide group (PEROXIDES) within an oxepin ring (OXEPINS).Dentists: Individuals licensed to practice DENTISTRY.Cholinergic Agonists: Drugs that bind to and activate cholinergic receptors.Parasympathomimetics: Drugs that mimic the effects of parasympathetic nervous system activity. Included here are drugs that directly stimulate muscarinic receptors and drugs that potentiate cholinergic activity, usually by slowing the breakdown of acetylcholine (CHOLINESTERASE INHIBITORS). Drugs that stimulate both sympathetic and parasympathetic postganglionic neurons (GANGLIONIC STIMULANTS) are not included here.Cassia: A plant genus of the family FABACEAE. Many species of this genus, including the medicinal C. senna and C. angustifolia, have been reclassified into the Senna genus (SENNA PLANT) and some to CHAMAECRISTA.Serotonin Antagonists: Drugs that bind to but do not activate serotonin receptors, thereby blocking the actions of serotonin or SEROTONIN RECEPTOR AGONISTS.Receptors, Serotonin, 5-HT1: A subclass of G-protein coupled SEROTONIN receptors that couple preferentially to GI-GO G-PROTEINS resulting in decreased intracellular CYCLIC AMP levels.Behavior, Animal: The observable response an animal makes to any situation.Learning Disorders: Conditions characterized by a significant discrepancy between an individual's perceived level of intellect and their ability to acquire new language and other cognitive skills. These disorders may result from organic or psychological conditions. Relatively common subtypes include DYSLEXIA, DYSCALCULIA, and DYSGRAPHIA.Nootropic Agents: Drugs used to specifically facilitate learning or memory, particularly to prevent the cognitive deficits associated with dementias. These drugs act by a variety of mechanisms. While no potent nootropic drugs have yet been accepted for general use, several are being actively investigated.Motor Activity: The physical activity of a human or an animal as a behavioral phenomenon.Parasympathetic Nervous System: The craniosacral division of the autonomic nervous system. The cell bodies of the parasympathetic preganglionic fibers are in brain stem nuclei and in the sacral spinal cord. They synapse in cranial autonomic ganglia or in terminal ganglia near target organs. The parasympathetic nervous system generally acts to conserve resources and restore homeostasis, often with effects reciprocal to the sympathetic nervous system.Drug Interactions: The action of a drug that may affect the activity, metabolism, or toxicity of another drug.Chlorfenvinphos: An organophosphorus cholinesterase inhibitor that is used as an insecticide and an acaricide.Plant Poisoning: Poisoning by the ingestion of plants or its leaves, berries, roots or stalks. The manifestations in both humans and animals vary in severity from mild to life threatening. In animals, especially domestic animals, it is usually the result of ingesting moldy or fermented forage.Azulenes: Compounds based on a seven-membered ring fused to a five-membered ring. Heat can rearrange them to NAPHTHALENES which have two fused six-membered rings. They are similar to guaiazulenes which are SESQUITERPENES with a six-membered ring fused to a five-membered ring.Diamines: Organic chemicals which have two amino groups in an aliphatic chain.Family Practice: A medical specialty concerned with the provision of continuing, comprehensive primary health care for the entire family.Biperiden: A muscarinic antagonist that has effects in both the central and peripheral nervous systems. It has been used in the treatment of arteriosclerotic, idiopathic, and postencephalitic parkinsonism. It has also been used to alleviate extrapyramidal symptoms induced by phenothiazine derivatives and reserpine.Spatial Behavior: Reactions of an individual or groups of individuals with relation to the immediate surrounding area including the animate or inanimate objects within that area.Retention (Psychology): The persistence to perform a learned behavior (facts or experiences) after an interval has elapsed in which there has been no performance or practice of the behavior.Arsenite Transporting ATPases: Efflux pumps that use the energy of ATP hydrolysis to pump arsenite across a membrane. They are primarily found in prokaryotic organisms, where they play a role in protection against excess intracellular levels of arsenite ions.Apomorphine: A derivative of morphine that is a dopamine D2 agonist. It is a powerful emetic and has been used for that effect in acute poisoning. It has also been used in the diagnosis and treatment of parkinsonism, but its adverse effects limit its use.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.Indans: Aryl CYCLOPENTANES that are a reduced (protonated) form of INDENES.Rats, Long-Evans: An outbred strain of rats developed in 1915 by crossing several Wistar Institute white females with a wild gray male. Inbred strains have been derived from this original outbred strain, including Long-Evans cinnamon rats (RATS, INBRED LEC) and Otsuka-Long-Evans-Tokushima Fatty rats (RATS, INBRED OLETF), which are models for Wilson's disease and non-insulin dependent diabetes mellitus, respectively.Pilocarpine: A slowly hydrolyzed muscarinic agonist with no nicotinic effects. Pilocarpine is used as a miotic and in the treatment of glaucoma.Magnetic Resonance Spectroscopy: Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).Family Planning Services: Health care programs or services designed to assist individuals in the planning of family size. Various methods of CONTRACEPTION can be used to control the number and timing of childbirths.Nicotinic Antagonists: Drugs that bind to nicotinic cholinergic receptors (RECEPTORS, NICOTINIC) and block the actions of acetylcholine or cholinergic agonists. Nicotinic antagonists block synaptic transmission at autonomic ganglia, the skeletal neuromuscular junction, and at central nervous system nicotinic synapses.Double-Blind Method: A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.Polyvinyl Chloride: A polyvinyl resin used extensively in the manufacture of plastics, including medical devices, tubing, and other packaging. It is also used as a rubber substitute.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.Arecoline: An alkaloid obtained from the betel nut (Areca catechu), fruit of a palm tree. It is an agonist at both muscarinic and nicotinic acetylcholine receptors. It is used in the form of various salts as a ganglionic stimulant, a parasympathomimetic, and a vermifuge, especially in veterinary practice. It has been used as a euphoriant in the Pacific Islands.Hippocampus: A curved elevation of GRAY MATTER extending the entire length of the floor of the TEMPORAL HORN of the LATERAL VENTRICLE (see also TEMPORAL LOBE). The hippocampus proper, subiculum, and DENTATE GYRUS constitute the hippocampal formation. Sometimes authors include the ENTORHINAL CORTEX in the hippocampal formation.Learning: Relatively permanent change in behavior that is the result of past experience or practice. The concept includes the acquisition of knowledge.Receptors, Serotonin: Cell-surface proteins that bind SEROTONIN and trigger intracellular changes which influence the behavior of cells. Several types of serotonin receptors have been recognized which differ in their pharmacology, molecular biology, and mode of action.Benzazepines: Compounds with BENZENE fused to AZEPINES.Choline O-Acetyltransferase: An enzyme that catalyzes the formation of acetylcholine from acetyl-CoA and choline. EC