Benserazide: An inhibitor of DOPA DECARBOXYLASE that does not enter the central nervous system. It is often given with LEVODOPA in the treatment of parkinsonism to prevent the conversion of levodopa to dopamine in the periphery, thereby increasing the amount that reaches the central nervous system and reducing the required dose. It has no antiparkinson actions when given alone.Levodopa: The naturally occurring form of DIHYDROXYPHENYLALANINE and the immediate precursor of DOPAMINE. Unlike dopamine itself, it can be taken orally and crosses the blood-brain barrier. It is rapidly taken up by dopaminergic neurons and converted to DOPAMINE. It is used for the treatment of PARKINSONIAN DISORDERS and is usually given with agents that inhibit its conversion to dopamine outside of the central nervous system.Antiparkinson Agents: Agents used in the treatment of Parkinson's disease. The most commonly used drugs act on the dopaminergic system in the striatum and basal ganglia or are centrally acting muscarinic antagonists.Aromatic-L-Amino-Acid Decarboxylases: An enzyme group with broad specificity. The enzymes decarboxylate a range of aromatic amino acids including dihydroxyphenylalanine (DOPA DECARBOXYLASE); TRYPTOPHAN; and HYDROXYTRYPTOPHAN.Dyskinesia, Drug-Induced: Abnormal movements, including HYPERKINESIS; HYPOKINESIA; TREMOR; and DYSTONIA, associated with the use of certain medications or drugs. Muscles of the face, trunk, neck, and extremities are most commonly affected. Tardive dyskinesia refers to abnormal hyperkinetic movements of the muscles of the face, tongue, and neck associated with the use of neuroleptic agents (see ANTIPSYCHOTIC AGENTS). (Adams et al., Principles of Neurology, 6th ed, p1199)Carbidopa: An inhibitor of DOPA DECARBOXYLASE, preventing conversion of LEVODOPA to dopamine. It is used in PARKINSON DISEASE to reduce peripheral adverse effects of LEVODOPA. It has no antiparkinson actions by itself.Droxidopa: A precursor of noradrenaline that is used in the treatment of parkinsonism. The racemic form (DL-threo-3,4-dihydroxyphenylserine) has also been used, and has been investigated in the treatment of orthostatic hypotension. There is a deficit of noradrenaline as well as of dopamine in Parkinson's disease and it has been proposed that this underlies the sudden transient freezing seen usually in advanced disease. Administration of DL-threo-3,4-dihydroxyphenylserine has been claimed to result in an improvement in this phenomenon but controlled studies have failed to demonstrate improvement. (Reynolds JEF(Ed): Martindale: The Extra Pharmacopoeia (electronic version). Micromedex, Inc, Englewood, CO, 1995)Adrenergic Agents: Drugs that act on adrenergic receptors or affect the life cycle of adrenergic transmitters. Included here are adrenergic agonists and antagonists and agents that affect the synthesis, storage, uptake, metabolism, or release of adrenergic transmitters.Hydrazines3,4-Dihydroxyphenylacetic Acid: A deaminated metabolite of LEVODOPA.Dihydroxyphenylalanine: A beta-hydroxylated derivative of phenylalanine. The D-form of dihydroxyphenylalanine has less physiologic activity than the L-form and is commonly used experimentally to determine whether the pharmacological effects of LEVODOPA are stereospecific.Parkinson Disease: A progressive, degenerative neurologic disease characterized by a TREMOR that is maximal at rest, retropulsion (i.e. a tendency to fall backwards), rigidity, stooped posture, slowness of voluntary movements, and a masklike facial expression. Pathologic features include loss of melanin containing neurons in the substantia nigra and other pigmented nuclei of the brainstem. LEWY BODIES are present in the substantia nigra and locus coeruleus but may also be found in a related condition (LEWY BODY DISEASE, DIFFUSE) characterized by dementia in combination with varying degrees of parkinsonism. (Adams et al., Principles of Neurology, 6th ed, p1059, pp1067-75)Dopamine Agents: Any drugs that are used for their effects on dopamine receptors, on the life cycle of dopamine, or on the survival of dopaminergic neurons.Drug Combinations: Single preparations containing two or more active agents, for the purpose of their concurrent administration as a fixed dose mixture.Biological Availability: The extent to which the active ingredient of a drug dosage form becomes available at the site of drug action or in a biological medium believed to reflect accessibility to a site of action.Tablets: Solid dosage forms, of varying weight, size, and shape, which may be molded or compressed, and which contain a medicinal substance in pure or diluted form. (Dorland, 28th ed)ArgentinaTherapeutic Equivalency: The relative equivalency in the efficacy of different modes of treatment of a disease, most often used to compare the efficacy of different pharmaceuticals to treat a given disease.Cross-Over Studies: Studies comparing two or more treatments or interventions in which the subjects or patients, upon completion of the course of one treatment, are switched to another. In the case of two treatments, A and B, half the subjects are randomly allocated to receive these in the order A, B and half to receive them in the order B, A. A criticism of this design is that effects of the first treatment may carry over into the period when the second is given. (Last, A Dictionary of Epidemiology, 2d ed)Lisuride: An ergot derivative that acts as an agonist at dopamine D2 receptors (DOPAMINE AGONISTS). It may also act as an antagonist at dopamine D1 receptors, and as an agonist at some serotonin receptors (SEROTONIN RECEPTOR AGONISTS).Copyright: It is a form of protection provided by law. In the United States this protection is granted to authors of original works of authorship, including literary, dramatic, musical, artistic, and certain other intellectual works. This protection is available to both published and unpublished works. (from Circular of the United States Copyright Office, 6/30/2008)Biochemical Processes: Chemical reactions or functions, enzymatic activities, and metabolic pathways of living things.Molecular Biology: A discipline concerned with studying biological phenomena in terms of the chemical and physical interactions of molecules.Laboratories: Facilities equipped to carry out investigative procedures.Systems Biology: Comprehensive, methodical analysis of complex biological systems by monitoring responses to perturbations of biological processes. Large scale, computerized collection and analysis of the data are used to develop and test models of biological systems.Biology: One of the BIOLOGICAL SCIENCE DISCIPLINES concerned with the origin, structure, development, growth, function, genetics, and reproduction of animals, plants, and microorganisms.EnglandDeep Brain Stimulation: Therapy for MOVEMENT DISORDERS, especially PARKINSON DISEASE, that applies electricity via stereotactic implantation of ELECTRODES in specific areas of the BRAIN such as the THALAMUS. The electrodes are attached to a neurostimulator placed subcutaneously.Subthalamic Nucleus: Lens-shaped structure on the inner aspect of the INTERNAL CAPSULE. The SUBTHALAMIC NUCLEUS and pathways traversing this region are concerned with the integration of somatic motor function.Basal Ganglia: Large subcortical nuclear masses derived from the telencephalon and located in the basal regions of the cerebral hemispheres.Globus Pallidus: The representation of the phylogenetically oldest part of the corpus striatum called the paleostriatum. It forms the smaller, more medial part of the lentiform nucleus.Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Neural Pathways: Neural tracts connecting one part of the nervous system with another.Endocrine Glands: Ductless glands that secrete HORMONES directly into the BLOOD CIRCULATION. These hormones influence the METABOLISM and other functions of cells in the body.Endocrine System: The system of glands that release their secretions (hormones) directly into the circulatory system. In addition to the ENDOCRINE GLANDS, included are the CHROMAFFIN SYSTEM and the NEUROSECRETORY SYSTEMS.Receptors, CCR10: CCR receptors with specificity for CHEMOKINE CCL27. They may play a specialized role in the cutaneous homing of LYMPHOCYTES.Adenylate Cyclase: An enzyme of the lyase class that catalyzes the formation of CYCLIC AMP and pyrophosphate from ATP. EC 4.6.1.1.Receptors, Dopamine D2: A subfamily of G-PROTEIN-COUPLED RECEPTORS that bind the neurotransmitter DOPAMINE and modulate its effects. D2-class receptor genes contain INTRONS, and the receptors inhibit ADENYLYL CYCLASES.Receptors, Dopamine D4: A subtype of dopamine D2 receptors that has high affinity for the antipsychotic CLOZAPINE.Morphine: The principal alkaloid in opium and the prototype opiate analgesic and narcotic. Morphine has widespread effects in the central nervous system and on smooth muscle.Chloral Hydrate: A hypnotic and sedative used in the treatment of INSOMNIA.Analgesics, Opioid: Compounds with activity like OPIATE ALKALOIDS, acting at OPIOID RECEPTORS. Properties include induction of ANALGESIA or NARCOSIS.Drug Interactions: The action of a drug that may affect the activity, metabolism, or toxicity of another drug.Injections, Spinal: Introduction of therapeutic agents into the spinal region using a needle and syringe.Analgesia: Methods of PAIN relief that may be used with or in place of ANALGESICS.Naloxone: A specific opiate antagonist that has no agonist activity. It is a competitive antagonist at mu, delta, and kappa opioid receptors.Materia Medica: Materials or substances used in the composition of traditional medical remedies. The use of this term in MeSH was formerly restricted to historical articles or those concerned with traditional medicine, but it can also refer to homeopathic remedies. Nosodes are specific types of homeopathic remedies prepared from causal agents or disease products.Pharmaceutical Preparations: Drugs intended for human or veterinary use, presented in their finished dosage form. Included here are materials used in the preparation and/or formulation of the finished dosage form.Palmitic Acids: A group of 16-carbon fatty acids that contain no double bonds.Scientific Misconduct: Intentional falsification of scientific data by presentation of fraudulent or incomplete or uncorroborated findings as scientific fact.Absorptiometry, Photon: A noninvasive method for assessing BODY COMPOSITION. It is based on the differential absorption of X-RAYS (or GAMMA RAYS) by different tissues such as bone, fat and other soft tissues. The source of (X-ray or gamma-ray) photon beam is generated either from radioisotopes such as GADOLINIUM 153, IODINE 125, or Americanium 241 which emit GAMMA RAYS in the appropriate range; or from an X-ray tube which produces X-RAYS in the desired range. It is primarily used for quantitating BONE MINERAL CONTENT, especially for the diagnosis of OSTEOPOROSIS, and also in measuring BONE MINERALIZATION.Citrus: A plant genus of the family RUTACEAE. They bear the familiar citrus fruits including oranges, grapefruit, lemons, and limes. There are many hybrids which makes the nomenclature confusing.Medicine, Chinese Traditional: A system of traditional medicine which is based on the beliefs and practices of the Chinese culture.