Dopamine: One of the catecholamine NEUROTRANSMITTERS in the brain. It is derived from TYROSINE and is the precursor to NOREPINEPHRINE and EPINEPHRINE. Dopamine is a major transmitter in the extrapyramidal system of the brain, and important in regulating movement. A family of receptors (RECEPTORS, DOPAMINE) mediate its action.Schizophrenia: A severe emotional disorder of psychotic depth characteristically marked by a retreat from reality with delusion formation, HALLUCINATIONS, emotional disharmony, and regressive behavior.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: Cell-surface proteins that bind dopamine with high affinity and trigger intracellular changes influencing the behavior of cells.Receptors, Dopamine D1: A subfamily of G-PROTEIN-COUPLED RECEPTORS that bind the neurotransmitter DOPAMINE and modulate its effects. D1-class receptor genes lack INTRONS, and the receptors stimulate ADENYLYL CYCLASES.Receptors, Dopamine D3: A subtype of dopamine D2 receptors that are highly expressed in the LIMBIC SYSTEM of the brain.Dopamine Agonists: Drugs that bind to and activate dopamine receptors.Dopamine Antagonists: Drugs that bind to but do not activate DOPAMINE RECEPTORS, thereby blocking the actions of dopamine or exogenous agonists. Many drugs used in the treatment of psychotic disorders (ANTIPSYCHOTIC AGENTS) are dopamine antagonists, although their therapeutic effects may be due to long-term adjustments of the brain rather than to the acute effects of blocking dopamine receptors. Dopamine antagonists have been used for several other clinical purposes including as ANTIEMETICS, in the treatment of Tourette syndrome, and for hiccup. Dopamine receptor blockade is associated with NEUROLEPTIC MALIGNANT SYNDROME.Receptors, Dopamine D4: A subtype of dopamine D2 receptors that has high affinity for the antipsychotic CLOZAPINE.Receptors, Dopamine D5: A subtype of dopamine D1 receptors that has higher affinity for DOPAMINE and differentially couples to GTP-BINDING PROTEINS.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.Schizophrenic Psychology: Study of mental processes and behavior of schizophrenics.Dopamine Plasma Membrane Transport Proteins: Sodium chloride-dependent neurotransmitter symporters located primarily on the PLASMA MEMBRANE of dopaminergic neurons. They remove DOPAMINE from the EXTRACELLULAR SPACE by high affinity reuptake into PRESYNAPTIC TERMINALS and are the target of DOPAMINE UPTAKE INHIBITORS.Antipsychotic Agents: Agents that control agitated psychotic behavior, alleviate acute psychotic states, reduce psychotic symptoms, and exert a quieting effect. They are used in SCHIZOPHRENIA; senile dementia; transient psychosis following surgery; or MYOCARDIAL INFARCTION; etc. These drugs are often referred to as neuroleptics alluding to the tendency to produce neurological side effects, but not all antipsychotics are likely to produce such effects. Many of these drugs may also be effective against nausea, emesis, and pruritus.Benzazepines: Compounds with BENZENE fused to AZEPINES.Dopamine Uptake Inhibitors: Drugs that block the transport of DOPAMINE into axon terminals or into storage vesicles within terminals. Most of the ADRENERGIC UPTAKE INHIBITORS also inhibit dopamine uptake.Corpus Striatum: Striped GRAY MATTER and WHITE MATTER consisting of the NEOSTRIATUM and paleostriatum (GLOBUS PALLIDUS). It is located in front of and lateral to the THALAMUS in each cerebral hemisphere. The gray substance is made up of the CAUDATE NUCLEUS and the lentiform nucleus (the latter consisting of the GLOBUS PALLIDUS and PUTAMEN). The WHITE MATTER is the INTERNAL CAPSULE.Quinpirole: A dopamine D2/D3 receptor agonist.Raclopride: A substituted benzamide that has antipsychotic properties. It is a dopamine D2 receptor (see RECEPTORS, DOPAMINE D2) antagonist.Schizophrenia, Paranoid: A chronic form of schizophrenia characterized primarily by the presence of persecutory or grandiose delusions, often associated with hallucination.Haloperidol: A phenyl-piperidinyl-butyrophenone that is used primarily to treat SCHIZOPHRENIA and other PSYCHOSES. It is also used in schizoaffective disorder, DELUSIONAL DISORDERS, ballism, and TOURETTE SYNDROME (a drug of choice) and occasionally as adjunctive therapy in INTELLECTUAL DISABILITY and the chorea of HUNTINGTON DISEASE. It is a potent antiemetic and is used in the treatment of intractable HICCUPS. (From AMA Drug Evaluations Annual, 1994, p279)Salicylamides: Amides of salicylic acid.Dopamine beta-HydroxylaseSulpiride: A dopamine D2-receptor antagonist. It has been used therapeutically as an antidepressant, antipsychotic, and as a digestive aid. (From Merck Index, 11th ed)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.Nucleus Accumbens: Collection of pleomorphic cells in the caudal part of the anterior horn of the LATERAL VENTRICLE, in the region of the OLFACTORY TUBERCLE, lying between the head of the CAUDATE NUCLEUS and the ANTERIOR PERFORATED SUBSTANCE. It is part of the so-called VENTRAL STRIATUM, a composite structure considered part of the BASAL GANGLIA.Spiperone: A spiro butyrophenone analog similar to HALOPERIDOL and other related compounds. It has been recommended in the treatment of SCHIZOPHRENIA.Neostriatum: The phylogenetically newer part of the CORPUS STRIATUM consisting of the CAUDATE NUCLEUS and PUTAMEN. It is often called simply the striatum.Schizophrenia, Disorganized: A type of schizophrenia characterized by frequent incoherence; marked loosening of associations, or grossly disorganized behavior and flat or grossly inappropriate affect that does not meet the criteria for the catatonic type; associated features include extreme social withdrawal, grimacing, mannerisms, mirror gazing, inappropriate giggling, and other odd behavior. (Dorland, 27th ed)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.Cocaine: An alkaloid ester extracted from the leaves of plants including coca. It is a local anesthetic and vasoconstrictor and is clinically used for that purpose, particularly in the eye, ear, nose, and throat. It also has powerful central nervous system effects similar to the amphetamines and is a drug of abuse. Cocaine, like amphetamines, acts by multiple mechanisms on brain catecholaminergic neurons; the mechanism of its reinforcing effects is thought to involve inhibition of dopamine uptake.Clozapine: A tricylic dibenzodiazepine, classified as an atypical antipsychotic agent. It binds several types of central nervous system receptors, and displays a unique pharmacological profile. Clozapine is a serotonin antagonist, with strong binding to 5-HT 2A/2C receptor subtype. It also displays strong affinity to several dopaminergic receptors, but shows only weak antagonism at the dopamine D2 receptor, a receptor commonly thought to modulate neuroleptic activity. Agranulocytosis is a major adverse effect associated with administration of this agent.Psychotic Disorders: Disorders in which there is a loss of ego boundaries or a gross impairment in reality testing with delusions or prominent hallucinations. (From DSM-IV, 1994)Schizophrenia, Childhood: An obsolete concept, historically used for childhood mental disorders thought to be a form of schizophrenia. It was in earlier versions of DSM but is now included within the broad concept of PERVASIVE DEVELOPMENT DISORDERS.Amphetamine: A powerful central nervous system stimulant and sympathomimetic. Amphetamine has multiple mechanisms of action including blocking uptake of adrenergics and dopamine, stimulation of release of monamines, and inhibiting monoamine oxidase. Amphetamine is also a drug of abuse and a psychotomimetic. The l- and the d,l-forms are included here. The l-form has less central nervous system activity but stronger cardiovascular effects. The d-form is DEXTROAMPHETAMINE.Prefrontal Cortex: The rostral part of the frontal lobe, bounded by the inferior precentral fissure in humans, which receives projection fibers from the MEDIODORSAL NUCLEUS OF THE THALAMUS. The prefrontal cortex receives afferent fibers from numerous structures of the DIENCEPHALON; MESENCEPHALON; and LIMBIC SYSTEM as well as cortical afferents of visual, auditory, and somatic origin.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.Dopamine and cAMP-Regulated Phosphoprotein 32: A phosphoprotein that was initially identified as a major target of DOPAMINE activated ADENYLYL CYCLASE in the CORPUS STRIATUM. It regulates the activities of PROTEIN PHOSPHATASE-1 and PROTEIN KINASE A, and it is a key mediator of the biochemical, electrophysiological, transcriptional, and behavioral effects of DOPAMINE.Behavior, Animal: The observable response an animal makes to any situation.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.Psychiatric Status Rating Scales: Standardized procedures utilizing rating scales or interview schedules carried out by health personnel for evaluating the degree of mental illness.Dopaminergic Neurons: Neurons whose primary neurotransmitter is DOPAMINE.Schizophrenia, Catatonic: A type of schizophrenia characterized by abnormality of motor behavior which may involve particular forms of stupor, rigidity, excitement or inappropriate posture.Homovanillic AcidMotor Activity: The physical activity of a human or an animal as a behavioral phenomenon.Domperidone: A specific blocker of dopamine receptors. It speeds gastrointestinal peristalsis, causes prolactin release, and is used as antiemetic and tool in the study of dopaminergic mechanisms.Ergolines: A series of structurally-related alkaloids that contain the ergoline backbone structure.Tyrosine 3-Monooxygenase: An enzyme that catalyzes the conversion of L-tyrosine, tetrahydrobiopterin, and oxygen to 3,4-dihydroxy-L-phenylalanine, dihydrobiopterin, and water. EC 1.14.16.2.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.Microdialysis: A technique for measuring extracellular concentrations of substances in tissues, usually in vivo, by means of a small probe equipped with a semipermeable membrane. Substances may also be introduced into the extracellular space through the membrane.Caudate Nucleus: Elongated gray mass of the neostriatum located adjacent to the lateral ventricle of the brain.2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine: A selective D1 dopamine receptor agonist used primarily as a research tool.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Substantia Nigra: The black substance in the ventral midbrain or the nucleus of cells containing the black substance. These cells produce DOPAMINE, an important neurotransmitter in regulation of the sensorimotor system and mood. The dark colored MELANIN is a by-product of dopamine synthesis.Neuropsychological Tests: Tests designed to assess neurological function associated with certain behaviors. They are used in diagnosing brain dysfunction or damage and central nervous system disorders or injury.Ventral Tegmental Area: A region in the MESENCEPHALON which is dorsomedial to the SUBSTANTIA NIGRA and ventral to the RED NUCLEUS. The mesocortical and mesolimbic dopaminergic systems originate here, including an important projection to the NUCLEUS ACCUMBENS. Overactivity of the cells in this area has been suspected to contribute to the positive symptoms of SCHIZOPHRENIA.Risperidone: A selective blocker of DOPAMINE D2 RECEPTORS and SEROTONIN 5-HT2 RECEPTORS that acts as an atypical antipsychotic agent. It has been shown to improve both positive and negative symptoms in the treatment of SCHIZOPHRENIA.Cognition Disorders: Disturbances in mental processes related to learning, thinking, reasoning, and judgment.Schizotypal Personality Disorder: A personality disorder in which there are oddities of thought (magical thinking, paranoid ideation, suspiciousness), perception (illusions, depersonalization), speech (digressive, vague, overelaborate), and behavior (inappropriate affect in social interactions, frequently social isolation) that are not severe enough to characterize schizophrenia.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Oxidopamine: A neurotransmitter analogue that depletes noradrenergic stores in nerve endings and induces a reduction of dopamine levels in the brain. Its mechanism of action is related to the production of cytolytic free-radicals.Putamen: The largest and most lateral of the BASAL GANGLIA lying between the lateral medullary lamina of the GLOBUS PALLIDUS and the EXTERNAL CAPSULE. It is part of the neostriatum and forms part of the LENTIFORM NUCLEUS along with the GLOBUS PALLIDUS.Catalepsy: A condition characterized by inactivity, decreased responsiveness to stimuli, and a tendency to maintain an immobile posture. The limbs tend to remain in whatever position they are placed (waxy flexibility). Catalepsy may be associated with PSYCHOTIC DISORDERS (e.g., SCHIZOPHRENIA, CATATONIC), nervous system drug toxicity, and other conditions.Sensory Gating: The ability of the BRAIN to suppress neuronal responses to external sensory inputs, such as auditory and visual stimuli. Sensory filtering (or gating) allows humans to block out irrelevant, meaningless, or redundant stimuli.Bromocriptine: A semisynthetic ergotamine alkaloid that is a dopamine D2 agonist. It suppresses prolactin secretion.Tetrahydronaphthalenes: Partially saturated 1,2,3,4-tetrahydronaphthalene compounds.Mesencephalon: The middle of the three primitive cerebral vesicles of the embryonic brain. Without further subdivision, midbrain develops into a short, constricted portion connecting the PONS and the DIENCEPHALON. Midbrain contains two major parts, the dorsal TECTUM MESENCEPHALI and the ventral TEGMENTUM MESENCEPHALI, housing components of auditory, visual, and other sensorimoter systems.Schizophrenic Language: The artificial language of schizophrenic patients - neologisms (words of the patient's own making with new meanings).Reward: An object or a situation that can serve to reinforce a response, to satisfy a motive, or to afford pleasure.Methamphetamine: A central nervous system stimulant and sympathomimetic with actions and uses similar to DEXTROAMPHETAMINE. The smokable form is a drug of abuse and is referred to as crank, crystal, crystal meth, ice, and speed.Startle Reaction: A complex involuntary response to an unexpected strong stimulus usually auditory in nature.alpha-Methyltyrosine: An inhibitor of the enzyme TYROSINE 3-MONOOXYGENASE, and consequently of the synthesis of catecholamines. It is used to control the symptoms of excessive sympathetic stimulation in patients with PHEOCHROMOCYTOMA. (Martindale, The Extra Pharmacopoeia, 30th ed)Butaclamol: A benzocycloheptapyridoisoquinolinol that has been used as an antipsychotic, especially in schizophrenia.PyrrolidinesCatechol O-Methyltransferase: Enzyme that catalyzes the movement of a methyl group from S-adenosylmethionone to a catechol or a catecholamine.Bipolar Disorder: A major affective disorder marked by severe mood swings (manic or major depressive episodes) and a tendency to remission and recurrence.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)Flupenthixol: A thioxanthene neuroleptic that, unlike CHLORPROMAZINE, is claimed to have CNS-activating properties. It is used in the treatment of psychoses although not in excited or manic patients. (From Martindale, The Extra Pharmacopoeia, 30th ed, p595)Magnetic Resonance Imaging: Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.Basal Ganglia: Large subcortical nuclear masses derived from the telencephalon and located in the basal regions of the cerebral hemispheres.Radioligand Assay: Quantitative determination of receptor (binding) proteins in body fluids or tissue using radioactively labeled binding reagents (e.g., antibodies, intracellular receptors, plasma binders).Delusions: A false belief regarding the self or persons or objects outside the self that persists despite the facts, and is not considered tenable by one's associates.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.Nerve Tissue ProteinsTropanes: N-methyl-8-azabicyclo[3.2.1]octanes best known for the ones found in PLANTS.Limbic System: A set of forebrain structures common to all mammals that is defined functionally and anatomically. It is implicated in the higher integration of visceral, olfactory, and somatic information as well as homeostatic responses including fundamental survival behaviors (feeding, mating, emotion). For most authors, it includes the AMYGDALA; EPITHALAMUS; GYRUS CINGULI; hippocampal formation (see HIPPOCAMPUS); HYPOTHALAMUS; PARAHIPPOCAMPAL GYRUS; SEPTAL NUCLEI; anterior nuclear group of thalamus, and portions of the basal ganglia. (Parent, Carpenter's Human Neuroanatomy, 9th ed, p744; NeuroNames, http://rprcsgi.rprc.washington.edu/neuronames/index.html (September 2, 1998)).Time Factors: Elements of limited time intervals, contributing to particular results or situations.Brief Psychiatric Rating Scale: A scale comprising 18 symptom constructs chosen to represent relatively independent dimensions of manifest psychopathology. The initial intended use was to provide more efficient assessment of treatment response in clinical psychopharmacology research; however, the scale was readily adapted to other uses. (From Hersen, M. and Bellack, A.S., Dictionary of Behavioral Assessment Techniques, p. 87)Stereotyped Behavior: Relatively invariant mode of behavior elicited or determined by a particular situation; may be verbal, postural, or expressive.Neural Pathways: Neural tracts connecting one part of the nervous system with another.Central Nervous System Stimulants: A loosely defined group of drugs that tend to increase behavioral alertness, agitation, or excitation. They work by a variety of mechanisms, but usually not by direct excitation of neurons. The many drugs that have such actions as side effects to their main therapeutic use are not included here.Hallucinations: Subjectively experienced sensations in the absence of an appropriate stimulus, but which are regarded by the individual as real. They may be of organic origin or associated with MENTAL DISORDERS.Vesicular Monoamine Transport Proteins: A family of vesicular amine transporter proteins that catalyze the transport and storage of CATECHOLAMINES and indolamines into SECRETORY VESICLES.PiperazinesSerotonin: A biochemical messenger and regulator, synthesized from the essential amino acid L-TRYPTOPHAN. In humans it is found primarily in the central nervous system, gastrointestinal tract, and blood platelets. Serotonin mediates several important physiological functions including neurotransmission, gastrointestinal motility, hemostasis, and cardiovascular integrity. Multiple receptor families (RECEPTORS, SEROTONIN) explain the broad physiological actions and distribution of this biochemical mediator.Brain Chemistry: Changes in the amounts of various chemicals (neurotransmitters, receptors, enzymes, and other metabolites) specific to the area of the central nervous system contained within the head. These are monitored over time, during sensory stimulation, or under different disease states.Nomifensine: An isoquinoline derivative that prevents dopamine reuptake into synaptosomes. The maleate was formerly used in the treatment of depression. It was withdrawn worldwide in 1986 due to the risk of acute hemolytic anemia with intravascular hemolysis resulting from its use. In some cases, renal failure also developed. (From Martindale, The Extra Pharmacopoeia, 30th ed, p266)Brain Mapping: Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.Synaptic Transmission: The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.Conditioning, Operant: Learning situations in which the sequence responses of the subject are instrumental in producing reinforcement. When the correct response occurs, which involves the selection from among a repertoire of responses, the subject is immediately reinforced.Biogenic Monoamines: Biogenic amines having only one amine moiety. Included in this group are all natural monoamines formed by the enzymatic decarboxylation of natural amino acids.Yawning: An involuntary deep INHALATION with the MOUTH open, often accompanied by the act of stretching.Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Delirium, Dementia, Amnestic, Cognitive Disorders: Cognitive disorders including delirium, dementia, and other cognitive disorders. These may be the result of substance use, trauma, or other causes.Hyperkinesis: Excessive movement of muscles of the body as a whole, which may be associated with organic or psychological disorders.Affective Disorders, Psychotic: Disorders in which the essential feature is a severe disturbance in mood (depression, anxiety, elation, and excitement) accompanied by psychotic symptoms such as delusions, hallucinations, gross impairment in reality testing, etc.Frontal Lobe: The part of the cerebral hemisphere anterior to the central sulcus, and anterior and superior to the lateral sulcus.Cerebral Cortex: The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulchi. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions.Case-Control Studies: Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.Parkinsonian Disorders: A group of disorders which feature impaired motor control characterized by bradykinesia, MUSCLE RIGIDITY; TREMOR; and postural instability. Parkinsonian diseases are generally divided into primary parkinsonism (see PARKINSON DISEASE), secondary parkinsonism (see PARKINSON DISEASE, SECONDARY) and inherited forms. These conditions are associated with dysfunction of dopaminergic or closely related motor integration neuronal pathways in the BASAL GANGLIA.Cocaine-Related Disorders: Disorders related or resulting from use of cocaine.Reaction Time: The time from the onset of a stimulus until a response is observed.Benzodiazepines: A group of two-ring heterocyclic compounds consisting of a benzene ring fused to a diazepine ring.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.Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Positron-Emission Tomography: An imaging technique using compounds labelled with short-lived positron-emitting radionuclides (such as carbon-11, nitrogen-13, oxygen-15 and fluorine-18) to measure cell metabolism. It has been useful in study of soft tissues such as CANCER; CARDIOVASCULAR SYSTEM; and brain. SINGLE-PHOTON EMISSION-COMPUTED TOMOGRAPHY is closely related to positron emission tomography, but uses isotopes with longer half-lives and resolution is lower.Pergolide: A long-acting dopamine agonist which has been used to treat PARKINSON DISEASE and HYPERPROLACTINEMIA but withdrawn from some markets due to potential for HEART VALVE DISEASES.Drug Interactions: The action of a drug that may affect the activity, metabolism, or toxicity of another drug.Parkinson Disease, Secondary: Conditions which feature clinical manifestations resembling primary Parkinson disease that are caused by a known or suspected condition. Examples include parkinsonism caused by vascular injury, drugs, trauma, toxin exposure, neoplasms, infections and degenerative or hereditary conditions. Clinical features may include bradykinesia, rigidity, parkinsonian gait, and masked facies. In general, tremor is less prominent in secondary parkinsonism than in the primary form. (From Joynt, Clinical Neurology, 1998, Ch38, pp39-42)Reserpine: An alkaloid found in the roots of Rauwolfia serpentina and R. vomitoria. Reserpine inhibits the uptake of norepinephrine into storage vesicles resulting in depletion of catecholamines and serotonin from central and peripheral axon terminals. It has been used as an antihypertensive and an antipsychotic as well as a research tool, but its adverse effects limit its clinical use.Genetic Predisposition to Disease: A latent susceptibility to disease at the genetic level, which may be activated under certain conditions.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.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.Norepinephrine: Precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic.Mice, Inbred C57BLSocial Adjustment: Adaptation of the person to the social environment. Adjustment may take place by adapting the self to the environment or by changing the environment. (From Campbell, Psychiatric Dictionary, 1996)Receptors, N-Methyl-D-Aspartate: A class of ionotropic glutamate receptors characterized by affinity for N-methyl-D-aspartate. NMDA receptors have an allosteric binding site for glycine which must be occupied for the channel to open efficiently and a site within the channel itself to which magnesium ions bind in a voltage-dependent manner. The positive voltage dependence of channel conductance and the high permeability of the conducting channel to calcium ions (as well as to monovalent cations) are important in excitotoxicity and neuronal plasticity.Image Processing, Computer-Assisted: A technique of inputting two-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.Receptor, Serotonin, 5-HT2A: A serotonin receptor subtype found widely distributed in peripheral tissues where it mediates the contractile responses of variety of tissues that contain SMOOTH MUSCLE. Selective 5-HT2A receptor antagonists include KETANSERIN. The 5-HT2A subtype is also located in BASAL GANGLIA and CEREBRAL CORTEX of the BRAIN where it mediates the effects of HALLUCINOGENS such as LSD.Mice, Knockout: Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.Memory, Short-Term: Remembrance of information for a few seconds to hours.Glutamic Acid: A non-essential amino acid naturally occurring in the L-form. Glutamic acid is the most common excitatory neurotransmitter in the CENTRAL NERVOUS SYSTEM.Fluphenazine: A phenothiazine used in the treatment of PSYCHOSES. Its properties and uses are generally similar to those of CHLORPROMAZINE.Basal Ganglia Diseases: Diseases of the BASAL GANGLIA including the PUTAMEN; GLOBUS PALLIDUS; claustrum; AMYGDALA; and CAUDATE NUCLEUS. DYSKINESIAS (most notably involuntary movements and alterations of the rate of movement) represent the primary clinical manifestations of these disorders. Common etiologies include CEREBROVASCULAR DISORDERS; NEURODEGENERATIVE DISEASES; and CRANIOCEREBRAL TRAUMA.Attention: Focusing on certain aspects of current experience to the exclusion of others. It is the act of heeding or taking notice or concentrating.Receptor, Adenosine A2A: A subclass of adenosine A2 receptors found in LEUKOCYTES, the SPLEEN, the THYMUS and a variety of other tissues. It is generally considered to be a receptor for ADENOSINE that couples to the GS, STIMULATORY G-PROTEIN.Reinforcement (Psychology): The strengthening of a conditioned response.Cognition: Intellectual or mental process whereby an organism obtains knowledge.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.Benztropine: A centrally active muscarinic antagonist that has been used in the symptomatic treatment of PARKINSON DISEASE. Benztropine also inhibits the uptake of dopamine.Autoradiography: The making of a radiograph of an object or tissue by recording on a photographic plate the radiation emitted by radioactive material within the object. (Dorland, 27th ed)Benzamides: BENZOIC ACID amides.Neurotransmitter Agents: Substances used for their pharmacological actions on any aspect of neurotransmitter systems. Neurotransmitter agents include agonists, antagonists, degradation inhibitors, uptake inhibitors, depleters, precursors, and modulators of receptor function.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).Catecholamines: A general class of ortho-dihydroxyphenylalkylamines derived from tyrosine.1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine: A dopaminergic neurotoxic compound which produces irreversible clinical, chemical, and pathological alterations that mimic those found in Parkinson disease.Psychoses, Substance-Induced: Psychotic organic mental disorders resulting from the toxic effect of drugs and chemicals or other harmful substance.MSH Release-Inhibiting Hormone: A hypothalamic tripeptide, enzymatic degradation product of OXYTOCIN, that inhibits the release of MELANOCYTE-STIMULATING HORMONES.Monoamine Oxidase: An enzyme that catalyzes the oxidative deamination of naturally occurring monoamines. It is a flavin-containing enzyme that is localized in mitochondrial membranes, whether in nerve terminals, the liver, or other organs. Monoamine oxidase is important in regulating the metabolic degradation of catecholamines and serotonin in neural or target tissues. Hepatic monoamine oxidase has a crucial defensive role in inactivating circulating monoamines or those, such as tyramine, that originate in the gut and are absorbed into the portal circulation. (From Goodman and Gilman's, The Pharmacological Basis of Therapeutics, 8th ed, p415) EC 1.4.3.4.Methylphenidate: A central nervous system stimulant used most commonly in the treatment of ATTENTION DEFICIT DISORDER in children and for NARCOLEPSY. Its mechanisms appear to be similar to those of DEXTROAMPHETAMINE. The d-isomer of this drug is referred to as DEXMETHYLPHENIDATE HYDROCHLORIDE.Functional Laterality: Behavioral manifestations of cerebral dominance in which there is preferential use and superior functioning of either the left or the right side, as in the preferred use of the right hand or right foot.Exploratory Behavior: The tendency to explore or investigate a novel environment. It is considered a motivation not clearly distinguishable from curiosity.Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.Locomotion: Movement or the ability to move from one place or another. It can refer to humans, vertebrate or invertebrate animals, and microorganisms.gamma-Aminobutyric Acid: The most common inhibitory neurotransmitter in the central nervous system.Tegmentum Mesencephali: Portion of midbrain situated under the dorsal TECTUM MESENCEPHALI. The two ventrolateral cylindrical masses or peduncles are large nerve fiber bundles providing a tract of passage between the FOREBRAIN with the HINDBRAIN. Ventral MIDBRAIN also contains three colorful structures: the GRAY MATTER (PERIAQUEDUCTAL GRAY), the black substance (SUBSTANTIA NIGRA), and the RED NUCLEUS.Endophenotypes: Measurable biological (physiological, biochemical, and anatomical features), behavioral (psychometric pattern) or cognitive markers that are found more often in individuals with a disease than in the general population. Because many endophenotypes are present before the disease onset and in individuals with heritable risk for disease such as unaffected family members, they can be used to help diagnose and search for causative genes.Gyrus Cinguli: One of the convolutions on the medial surface of the CEREBRAL HEMISPHERES. It surrounds the rostral part of the brain and CORPUS CALLOSUM and forms part of the LIMBIC SYSTEM.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.Neural Inhibition: The function of opposing or restraining the excitation of neurons or their target excitable cells.Dominance, Cerebral: Dominance of one cerebral hemisphere over the other in cerebral functions.MPTP Poisoning: A condition caused by the neurotoxin MPTP which causes selective destruction of nigrostriatal dopaminergic neurons. Clinical features include irreversible parkinsonian signs including rigidity and bradykinesia (PARKINSON DISEASE, SECONDARY). MPTP toxicity is also used as an animal model for the study of PARKINSON DISEASE. (Adams et al., Principles of Neurology, 6th ed, p1072; Neurology 1986 Feb;36(2):250-8)Carbon Radioisotopes: Unstable isotopes of carbon that decay or disintegrate emitting radiation. C atoms with atomic weights 10, 11, and 14-16 are radioactive carbon isotopes.Electric Stimulation: Use of electric potential or currents to elicit biological responses.Cyclic AMP: An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.Prolactin: A lactogenic hormone secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). It is a polypeptide of approximately 23 kD. Besides its major action on lactation, in some species prolactin exerts effects on reproduction, maternal behavior, fat metabolism, immunomodulation and osmoregulation. Prolactin receptors are present in the mammary gland, hypothalamus, liver, ovary, testis, and prostate.Nicotine: Nicotine is highly toxic alkaloid. It is the prototypical agonist at nicotinic cholinergic receptors where it dramatically stimulates neurons and ultimately blocks synaptic transmission. Nicotine is also important medically because of its presence in tobacco smoke.Extracellular Space: Interstitial space between cells, occupied by INTERSTITIAL FLUID as well as amorphous and fibrous substances. For organisms with a CELL WALL, the extracellular space includes everything outside of the CELL MEMBRANE including the PERIPLASM and the cell wall.Self Administration: Administration of a drug or chemical by the individual under the direction of a physician. It includes administration clinically or experimentally, by human or animal.Psychomotor Performance: The coordination of a sensory or ideational (cognitive) process and a motor activity.Temporal Lobe: Lower lateral part of the cerebral hemisphere responsible for auditory, olfactory, and semantic processing. It is located inferior to the lateral fissure and anterior to the OCCIPITAL LOBE.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.Medial Forebrain Bundle: A complex group of fibers arising from the basal olfactory regions, the periamygdaloid region, and the septal nuclei, and passing to the lateral hypothalamus. Some fibers continue into the tegmentum.Benzothiazoles: Compounds with a benzene ring fused to a thiazole ring.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Conditioning (Psychology): A general term referring to the learning of some particular response.Methylazoxymethanol Acetate: The aglycone of CYCASIN. It acts as a potent carcinogen and neurotoxin and inhibits hepatic DNA, RNA, and protein synthesis.Synaptosomes: Pinched-off nerve endings and their contents of vesicles and cytoplasm together with the attached subsynaptic area of the membrane of the post-synaptic cell. They are largely artificial structures produced by fractionation after selective centrifugation of nervous tissue homogenates.Polymorphism, Single Nucleotide: A single nucleotide variation in a genetic sequence that occurs at appreciable frequency in the population.Serotonin Antagonists: Drugs that bind to but do not activate serotonin receptors, thereby blocking the actions of serotonin or SEROTONIN RECEPTOR AGONISTS.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.National Institute of Mental Health (U.S.): A component of the NATIONAL INSTITUTES OF HEALTH concerned with research, overall planning, promoting, and administering mental health programs and research. It was established in 1949.Memory Disorders: Disturbances in registering an impression, in the retention of an acquired impression, or in the recall of an impression. Memory impairments are associated with DEMENTIA; CRANIOCEREBRAL TRAUMA; ENCEPHALITIS; ALCOHOLISM (see also ALCOHOL AMNESTIC DISORDER); SCHIZOPHRENIA; and other conditions.Piperidines: A family of hexahydropyridines.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.Hydroxydopamines: Dopamines with a hydroxy group substituted in one or more positions.Oxazines: Six-membered heterocycles containing an oxygen and a nitrogen.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.Nerve Net: A meshlike structure composed of interconnecting nerve cells that are separated at the synaptic junction or joined to one another by cytoplasmic processes. In invertebrates, for example, the nerve net allows nerve impulses to spread over a wide area of the net because synapses can pass information in any direction.Binding, Competitive: The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.Electrochemical Techniques: The utilization of an electrical current to measure, analyze, or alter chemicals or chemical reactions in solution, cells, or tissues.Motivation: Those factors which cause an organism to behave or act in either a goal-seeking or satisfying manner. They may be influenced by physiological drives or by external stimuli.Pimozide: A diphenylbutylpiperidine that is effective as an antipsychotic agent and as an alternative to HALOPERIDOL for the suppression of vocal and motor tics in patients with Tourette syndrome. Although the precise mechanism of action is unknown, blockade of postsynaptic dopamine receptors has been postulated. (From AMA Drug Evaluations Annual, 1994, p403)DibenzothiazepinesElectroencephalography: Recording of electric currents developed in the brain by means of electrodes applied to the scalp, to the surface of the brain, or placed within the substance of the brain.Acoustic Stimulation: Use of sound to elicit a response in the nervous system.Thinking: Mental activity, not predominantly perceptual, by which one apprehends some aspect of an object or situation based on past learning and experience.Dyskinesias: Abnormal involuntary movements which primarily affect the extremities, trunk, or jaw that occur as a manifestation of an underlying disease process. Conditions which feature recurrent or persistent episodes of dyskinesia as a primary manifestation of disease may be referred to as dyskinesia syndromes (see MOVEMENT DISORDERS). Dyskinesias are also a relatively common manifestation of BASAL GANGLIA DISEASES.Cues: Signals for an action; that specific portion of a perceptual field or pattern of stimuli to which a subject has learned to respond.Evoked Potentials, Auditory: The electric response evoked in the CEREBRAL CORTEX by ACOUSTIC STIMULATION or stimulation of the AUDITORY PATHWAYS.
  • Dopamine promotes neuronal differentiation, maintenance, and survival ( 1 - 4 ) by modulating the transcription of different genes. (pnas.org)
  • In the largest genetic study of its kind, published in Nature , we discovered not just a few, but more than 100 specific regions - or loci - of the genome which contain genes that affect risk, and have been able to identify a genetic link to a protein that is the only known target in schizophrenia drug treatment. (theconversation.com)
  • It has been known for a long time that genes play a big part in schizophrenia. (theconversation.com)
  • If specific genes that affect risk can be identified, researchers can then figure out what these genes do, which will in turn tell us what sorts of things might be going wrong in schizophrenia. (theconversation.com)
  • But the genetics of schizophrenia is complicated, meaning that in any one person, many genes are involved and that in different people, different sets of genes are involved. (theconversation.com)
  • Some of the genes that have been linked to schizophrenia are involved in biological processes that are prime suspects for contributing to the disorder. (theconversation.com)
  • However most of the findings involve genes whose functions are not evidently related to previous hypotheses, which means they can give us entirely new insights into how the disorder is caused. (theconversation.com)
  • However, having these genes doesn't necessarily mean you'll develop schizophrenia. (thekateearl.com)
  • While this is higher than in the general population, where the chance is about 1 in 100, it suggests genes aren't the only factor influencing the development of schizophrenia. (thekateearl.com)
  • Genes, environment and schizophrenia. (paperdue.com)
  • If a specific gene is suggested to be involved in schizophrenia by human genetic studies, the role of the gene should be examined in detail by using animals that carry abnormal expression and/or function of the genes [ 22 ]. (biomedcentral.com)
  • Firstly, while a definitive cause of schizophrenia still eludes us, an abundance of research has identified a wide array of biological and psychosocial risk factors and these aetiological factors will be outlined. (ukessays.com)
  • The cause of schizophrenia remains unclear, though much evidence suggests that it may be produced by an excess transmission of dopamine (DA) in selected brain regions [ 1 ]. (biomedcentral.com)
  • NSC dysfunction has also been shown to be a cause of schizophrenia [7, (scirp.org)
  • I present here a complementary hypothesis based on evidence showing that chronic exposure to antipsychotic medications can induce supersensitivity within the brain's dopamine systems, and that this in turn can enhance the rewarding and incentive motivational effects of drugs and reward cues. (ovid.com)
  • Social isolation has also been found to induce schizophrenia-like changes in animals ( 27 , 28 , 29 ). (science.blog)
  • To validate this hypothesis, the ability of APZ to induce motor-function behaviors associated with equilibrium and rotation asymmetry in a mouse model of middle cerebral artery occlusion (MCAO) was evaluated. (spandidos-publications.com)
  • Thus, it remains unclear what, if any, the direct role D2R play in the pathophysiology of schizophrenia. (biomedcentral.com)
  • The most well-known and respected hypothesis with regards to the pathophysiology of schizophrenia began in the 1990s and consisted primarily of the notion there is a problem with the dopamine levels in the brain of schizophrenics. (nursingcrib.com)
  • That said, it may not be the only neurotransmitter involved in the pathophysiology of schizophrenia. (nursingcrib.com)
  • Additional studies affecting the pathophysiology of schizophrenia include suggestions that maternal factors such as infection, malnutrician, location of birth, season of birth, and delivery, may play a significant part in the formation and subsequent appearance of schizophrenia. (nursingcrib.com)
  • Another aspect of the pathophysiology of schizophrenia that has been explored in relative detail is that of genetics, and their relation to the likelihood of immediate relatives being born with the disease. (nursingcrib.com)
  • Though there are many theories and hypotheses regarding the pathophysiology of schizophrenia, there is, unfortunately, still no cure for the disease. (nursingcrib.com)