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Monoamine Depleting Agent
Monoamine-depleting agents are a group of drugs which reversibly deplete one or more of the monoamine neurotransmittersserotonin, dopamine, and norepinephrine. One mechanism of action, mechanism by which these agents act is by reuptake inhibitor, inhibiting reuptake by the vesicular monoamine transporters, VMAT1 and VMAT2. Examples of monoamine-depleting agents include deutetrabenazine, methyldopa, oxypertine, reserpine, tetrabenazine, and valbenazine. Tetrabenazine selectively depletes dopamine at low doses and is used as an animal model of amotivation. Monoamine synthesis inhibitors, such as the tryptophan hydroxylase enzyme inhibitor, inhibitor and serotonin synthesis inhibitor para-chlorophenylalanine, ''para''-chlorophenylalanine (PCPA or fenclonine), also act as monoamine-depleting agents, as do various other agents, for instance monoaminergic neurotoxins. See also * Monoamine reuptake inhibitor * Monoamine releasing agent * Tetrabenazine#Animal model of motivational dysfu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reserpine
Reserpine is a drug that is used for the treatment of hypertension, high blood pressure, usually in combination with a thiazide diuretic or vasodilator. Large clinical trials have shown that combined treatment with reserpine plus a thiazide diuretic reduces mortality of people with hypertension. Although the use of reserpine as a solo drug has declined since it was first approved by the FDA in 1955, the combined use of reserpine and a thiazide diuretic or vasodilator is still recommended in patients who do not achieve adequate lowering of blood pressure with first-line drug treatment alone. The reserpine-hydrochlorothiazide combo pill was the 17th most commonly prescribed of the 43 combination antihypertensive pills available in 2012. The antihypertensive actions of reserpine are largely due to its antinoradrenergic effects, which are a result of its ability to deplete catecholamines (among other monoamine neurotransmitters) from peripheral nervous system, peripheral sympathetic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrabenazine
Tetrabenazine is a drug for the symptomatic treatment of hyperkinetic movement disorders. It is sold under the brand names Nitoman and Xenazine among others. On August 15, 2008, the US Food and Drug Administration (FDA) approved the use of tetrabenazine to treat chorea associated with Huntington's disease. Although other drugs had been used "off-label", tetrabenazine was the first approved treatment for Huntington's disease in the United States. The compound has been known since the 1950s. Medical uses Tetrabenazine is used as a treatment, but not as a cure, for hyperkinetic disorders such as: * Huntington's disease – specifically, the chorea associated with it * Tourette syndrome and other tic disorders * Tardive dyskinesia, a serious and sometimes irreversible side effect of long-term use of many antipsychotics, mainly typical antipsychotics * Hemiballismus, spontaneous flinging limb movements due to contra-lateral subthalamic nucleus damage Tetrabenazine has been used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoamine Releasing Agent
A monoamine releasing agent (MRA), or simply monoamine releaser, is a drug that induces the release of one or more monoamine neurotransmitters from the presynaptic neuron into the synapse, leading to an increase in the extracellular concentrations of the neurotransmitters and hence enhanced signaling by those neurotransmitters. The monoamine neurotransmitters include serotonin, norepinephrine, and dopamine; MRAs can induce the release of one or more of these neurotransmitters. MRAs work by reversing the direction of the monoamine transporters (MATs), including the serotonin transporter (SERT), norepinephrine transporter (NET), and/or dopamine transporter (DAT), causing them to promote efflux of non-vesicular cytoplasmic monoamine neurotransmitter rather than reuptake of synaptic monoamine neurotransmitter. Many, but not all MRAs, also reverse the direction of the vesicular monoamine transporter 2 (VMAT2), thereby additionally resulting in efflux of vesicular monoamine neuro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoamine Reuptake Inhibitor
A monoamine reuptake inhibitor (MRI) is a drug that acts as a reuptake inhibitor of one or more of the three major monoamine neurotransmitters serotonin, norepinephrine, and dopamine by blocking the action of one or more of the respective monoamine transporters (MATs), which include the serotonin transporter (SERT), norepinephrine transporter (NET), and dopamine transporter (DAT). This in turn results in an increase in the synaptic concentrations of one or more of these neurotransmitters and therefore an increase in monoaminergic neurotransmission. Uses The majority of currently approved antidepressants act predominantly or exclusively as MRIs, including the selective serotonin reuptake inhibitors (SSRIs), serotonin–norepinephrine reuptake inhibitors (SNRIs), and almost all of the tricyclic antidepressants (TCAs). Many psychostimulants used either in the treatment of or as appetite suppressants in the treatment of obesity also behave as MRIs, although notably amphetamine (and m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoaminergic Neurotoxin
A monoamine neurotoxin, or monoaminergic neurotoxin, is a drug that selectively damages or destroys monoaminergic neurons. Monoaminergic neurons are neurons that signal via stimulation by monoamine neurotransmitters including serotonin, dopamine, and norepinephrine. Examples of monoamine neurotoxins include the serotonergic neurotoxins ''para''-chloroamphetamine (PCA), methylenedioxymethamphetamine (MDMA), and 5,7-dihydroxytryptamine (5,7-DHT); the dopaminergic neurotoxins oxidopamine (6-hydroxydopamine), MPTP, and methamphetamine; and the noradrenergic neurotoxins oxidopamine and DSP-4. In the case of serotonergic neurotoxins like MDMA, research suggests that simultaneous induction of serotonin and dopamine release, serotonin depletion, dopamine uptake and metabolism, hyperthermia, oxidative stress and antioxidant depletion, and/or drug metabolites may all be involved in the neurotoxicity. On the other hand, there is evidence that drug metabolites may not be involved. So ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Para-chlorophenylalanine
Fenclonine, also known as ''para''-chlorophenylalanine (PCPA), acts as a selective and irreversible inhibitor of tryptophan hydroxylase, which is a rate-limiting enzyme in the biosynthesis of serotonin. It has been used experimentally to treat carcinoid syndrome, but the side effects, mostly hypersensitivity reactions and psychiatric disturbances, have prevented development for this use. The effects of serotonin depletion from fenclonine are so drastic that serotonin cannot even be detected immunohistochemically within the first day after administration of a control dose. Tryptophan hydroxylase activity can be detected neither in cell bodies or nerve terminals. After one week 10% of control values (the baseline extrapolated for the study) had replenished in the raphe nucleus, and after two weeks from initial treatment as much was again detected in the hypothalamus region. Aromatic L-amino acid decarboxylase (AADC) levels were at no time affected. It is used in scientific resea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme Inhibitor
An enzyme inhibitor is a molecule that binds to an enzyme and blocks its Enzyme activity, activity. Enzymes are proteins that speed up chemical reactions necessary for life, in which Substrate (biochemistry), substrate molecules are converted into Product (chemistry), products. An enzyme Enzyme catalysis, facilitates a specific chemical reaction by binding the substrate to its active site, a specialized area on the enzyme that accelerates the Rate-determining step, most difficult step of the reaction. An enzyme inhibitor stops ("inhibits") this process, either by binding to the enzyme's active site (thus preventing the substrate itself from binding) or by binding to another site on the enzyme such that the enzyme's catalysis of the reaction is blocked. Enzyme inhibitors may bind Reversible reaction, reversibly or irreversibly. Irreversible inhibitors form a Covalent bond, chemical bond with the enzyme such that the enzyme is inhibited until the chemical bond is broken. By cont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tryptophan Hydroxylase
Tryptophan hydroxylase (TPH) is an enzyme () involved in the synthesis of the monoamine neurotransmitter serotonin. Tyrosine hydroxylase, phenylalanine hydroxylase, and tryptophan hydroxylase together constitute the family of biopterin-dependent aromatic amino acid hydroxylases. TPH catalyzes the following chemical reaction : L-tryptophan + tetrahydrobiopterin + O2 \rightleftharpoons 5-Hydroxytryptophan + dihydrobiopterin + H2O It employs one additional cofactor, iron. Function It is responsible for addition of the -OH group ( hydroxylation) to the 5 position to form the amino acid 5-hydroxytryptophan (5-HTP), which is the initial and rate-limiting step in the synthesis of the neurotransmitter serotonin. It is also the first enzyme in the synthesis of melatonin. Tryptophan hydroxylase (TPH), tyrosine hydroxylase (TH) and phenylalanine hydroxylase (PAH) are members of a superfamily of aromatic amino acid hydroxylases, catalyzing key steps in important metabolic p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amotivation
Amotivational syndrome is a chronic psychiatric disorder characterized by signs that are linked to cognitive and emotional states such as detachment, blunted emotion and drives, executive functions like memory and attention, disinterest, passivity, apathy, and a general lack of motivation. This syndrome can be branched into two subtypes: marijuana amotivational syndrome, or cannabis-induced amotivational syndrome, which is caused by usage of or dependency on that substance, and is primarily associated with long-term effects of cannabis use, and SSRI-induced amotivational syndrome or SSRI-induced apathy, caused by the intake of SSRI medication dosage. According to the Handbook of Clinical Psychopharmacology for Therapists, amotivational syndrome is listed as a possible side effect of SSRIs in the treatment of clinical depression. It is a disorder of diminished motivation. Signs and symptoms Amotivational syndrome has been suspected to affect the frontal cortex or frontal lobe of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal Model
An animal model (short for animal disease model) is a living, non-human, often genetic-engineered animal used during the research and investigation of human disease, for the purpose of better understanding the disease process without the risk of harming a human. Although biological activity in an animal model does not ensure an effect in humans, many drugs, treatments and cures for human diseases are developed in part with the guidance of animal models. Animal models representing specific taxonomic groups in the research and study of developmental processes are also referred to as model organisms. There are three main types of animal models: Homologous, Isomorphic and Predictive. Homologous animals have the same causes, symptoms and treatment options as would humans who have the same disease. Isomorphic animals share the same symptoms and treatments, only. Predictive models are similar to a particular human disease in only a couple of aspects. However, these are useful in isolating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valbenazine
Valbenazine, sold under the brand name Ingrezza, is a medication used to treat tardive dyskinesia. It acts as a vesicular monoamine transporter 2 (VMAT2) inhibitor. Medical use Valbenazine is used to treat tardive dyskinesia in adults. Tardive dyskinesia is a drug-induced neurological injury characterized by involuntary movements. The clinical trials that led to the approval of valbenazine by the US Food and Drug Administration (FDA) were six weeks in duration. An industry-sponsored study has studied the use of valbenazine for up to 48 weeks, in which it was found to be safe and effective for maintaining short-term (6 week) improvements in tardive dyskinesia. Contraindications There are no contraindications for the use of valbenazine according to the prescribing information. Adverse effects Side effects may include sleepiness or QT prolongation. Significant prolongation has not yet been observed at recommended dosage levels, however, those taking inhibitors of the liver en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
