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6-OHDA
Oxidopamine, also known as 6-hydroxydopamine (6-OHDA) or 2,4,5-trihydroxyphenethylamine, is a neurotoxic synthetic organic compound used by researchers to selectively destroy dopaminergic and noradrenergic neurons in the brain. The main use for oxidopamine in scientific research is to induce Parkinsonism in laboratory animals by lesioning the dopaminergic neurons of the substantia nigra pars compacta, in order to develop and test new medicines and treatments for Parkinson's disease. History The neurontoxin oxidopamine has first been described in 1959. Years later, in 1968 the first model exploiting oxidopamine neurotoxicity was developed by Ungerstedt, obtaining an animal model of akineasia with a very high mortality rate. Ever since, oxidopamine has become an abundantly used neurotoxin for making animal models with Parkinson’s disease. Usage The toxin oxidopamine, an antagonist of the neurotransmitter dopamine, and is commonly used for making experimental animal model ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
5,7-Dihydroxytryptamine
5,7-Dihydroxytryptamine (5,7-DHT) is a purported neurotoxin used in scientific research to decrease concentrations of serotonin in the brain. The mechanism behind this effect is not well understood, but it is speculated to selectively destroy serotonergic neurons, in a manner similar to the dopaminergic neurotoxicity of 6-hydroxydopamine (6-OHDA). What is known is that this compound is in fact not selective in depleting serotonin content, but also depletes norepinephrine. To selectively deplete serotonin stores, it is commonly administered in conjunction with desmethylimipramine (desipramine),Martin-Iverson, M.T., Leclere, J.F. and Fibiger, H.C., Cholinergic-dopaminergic interactions and the mechanisms of action of antidepressants, ''European Journal of Pharmacology'', 94 (1983) 193–201. which inhibits the norepinephrine transporter. See also * DSP-4 * 6-Hydroxydopamine Oxidopamine, also known as 6-hydroxydopamine (6-OHDA) or 2,4,5-trihydroxyphenethylamine, is a neurotoxic s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nigrostriatal Pathway
The nigrostriatal pathway is a bilateral dopaminergic pathway in the brain that connects the substantia nigra pars compacta (SNc) in the midbrain with the dorsal striatum (i.e., the caudate nucleus and putamen) in the forebrain. It is one of the four major dopamine pathways in the brain, and is critical in the production of movement as part of a system called the basal ganglia motor loop. Dopaminergic neurons of this pathway release dopamine from axon terminals that synapse onto GABAergic medium spiny neurons (MSNs), also known as spiny projection neurons (SPNs), located in the striatum. Degeneration of dopaminergic neurons in the SNc is one of the main pathological features of Parkinson's disease, leading to a marked reduction in dopamine function and the symptomatic motor deficits of Parkinson's disease including hypokinesia, tremors, rigidity, and postural imbalance. Anatomy The connection between the substantia nigra pars compacta and the dorsal striatum is mediated via do ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurotoxin
Neurotoxins are toxins that are destructive to nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insultsSpencer 2000 that can adversely affect function in both developing and mature nervous tissue.Olney 2002 The term can also be used to classify endogenous compounds, which, when abnormally contacted, can prove neurologically toxic. Though neurotoxins are often neurologically destructive, their ability to specifically target neural components is important in the study of nervous systems. Common examples of neurotoxins include lead, ethanol (drinking alcohol), glutamate,Choi 1987 nitric oxide, botulinum toxin (e.g. Botox), tetanus toxin,Simpson 1986 and tetrodotoxin. Some substances such as nitric oxide and glutamate are in fact essential for proper function of the body and only exert neurotoxic effects at excessive concentrations. Neurotoxins inhibit neuron control over ion concentrations across the cell membrane, or commu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MPTP
MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) is a prodrug to the neurotoxin MPP+, which causes permanent symptoms of Parkinson's disease by destroying dopaminergic neurons in the substantia nigra of the brain. It has been used to study disease models in various animal studies. While MPTP itself has no psychoactive effects, the compound may be accidentally produced during the manufacture of MPPP, a synthetic opioid drug with effects similar to those of morphine and pethidine (meperidine). The Parkinson-inducing effects of MPTP were first discovered following accidental injection as a result of contaminated MPPP. Toxicity Injection of MPTP causes rapid onset of Parkinsonism, hence users of MPPP contaminated with MPTP will develop these symptoms. MPTP itself is not toxic, and as a lipophilic compound can cross the blood–brain barrier. Once inside the brain, MPTP is metabolized into the toxic cation 1-methyl-4-phenylpyridinium (MPP+) by the enzyme monoamine oxidase B ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FAUC50
FAUC50 is a covalent agonist of the β2 adrenoceptor. It has been used as a template to form covalent agonists for other receptors. References Dopamine agonists Irreversible agonists {{nervous-system-drug-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotenone
Rotenone is an odorless, colorless, crystalline isoflavone used as a broad-spectrum insecticide, piscicide, and pesticide. It occurs naturally in the seeds and stems of several plants, such as the jicama vine plant, and the roots of several members of Fabaceae. It was the first described member of the family of chemical compounds known as rotenoids. Discovery The earliest record of the now-known rotenone-containing plants used for killing leaf-eating caterpillars was in 1848, and for centuries, the same plants were used to poison fish. The active chemical component was first isolated in 1895 by a French botanist, Emmanuel Geoffroy, who called it ''nicouline'', from a specimen of ''Robinia nicou'', now called '' Lonchocarpus nicou'', while traveling in French Guiana. He wrote about this research in his thesis, published in 1895 after his death from a parasitic disease. In 1902 Kazuo Nagai, Japanese chemical engineer of the Government-General of Taiwan, isolated a pure cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norsalsolinol
Norsalsolinol is a chemical compound that is produced naturally in the body through metabolism of dopamine. It has been shown to be a selective dopaminergic neurotoxin, and has been suggested as a possible cause of neurodegenerative conditions such as Parkinson's disease and the brain damage associated with alcoholism, although evidence for a causal relationship is unclear. (R)-Salsolinol which has been shown to be a product of ethanol metabolism, stereospecifically induces behavioral sensitization and leads to excessive alcohol intake in rats See also * 6-Hydroxydopamine Oxidopamine, also known as 6-hydroxydopamine (6-OHDA) or 2,4,5-trihydroxyphenethylamine, is a neurotoxic synthetic organic compound used by researchers to selectively destroy dopaminergic and noradrenergic neurons in the brain. The main use for o ... * MPTP * Rotenone References Tetrahydroisoquinolines Catechols {{nervous-system-drug-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DSP-4
''For the Super NES enhancement chip see List of Super NES enhancement chips'' DSP-4, or N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine, is a neurotoxin selective for noradrenergic neurons, capable of crossing the blood–brain barrier. It exerts transient effects in peripheral sympathetic neurons, but more permanent changes within neurons of the central nervous system. It can induce long-term depletion in cortical and spinal levels of noradrenaline. See also * 5,7-Dihydroxytryptamine * MPTP MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) is a prodrug to the neurotoxin MPP+, which causes permanent symptoms of Parkinson's disease by destroying dopaminergic neurons in the substantia nigra of the brain. It has been used to study d ... * Oxidopamine References Neurotoxins Bromoarenes Organochlorides Amines Nitrogen mustards Chloroethyl compounds {{Neurotoxin-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood–brain Barrier
The blood–brain barrier (BBB) is a highly selective semipermeable border of endothelial cells that prevents solutes in the circulating blood from ''non-selectively'' crossing into the extracellular fluid of the central nervous system where neurons reside. The blood–brain barrier is formed by endothelial cells of the capillary wall, astrocyte end-feet ensheathing the capillary, and pericytes embedded in the capillary basement membrane. This system allows the passage of some small molecules by passive diffusion, as well as the selective and active transport of various nutrients, ions, organic anions, and macromolecules such as glucose and amino acids that are crucial to neural function. The blood–brain barrier restricts the passage of pathogens, the diffusion of solutes in the blood, and large or hydrophilic molecules into the cerebrospinal fluid, while allowing the diffusion of hydrophobic molecules (O2, CO2, hormones) and small non-polar molecules. Cells of the barrier ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxicity
Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell ( cytotoxicity) or an organ such as the liver ( hepatotoxicity). By extension, the word may be metaphorically used to describe toxic effects on larger and more complex groups, such as the family unit or society at large. Sometimes the word is more or less synonymous with poisoning in everyday usage. A central concept of toxicology is that the effects of a toxicant are dose-dependent; even water can lead to water intoxication when taken in too high a dose, whereas for even a very toxic substance such as snake venom there is a dose below which there is no detectable toxic effect. Toxicity is species-specific, making cross-species analysis problematic. Newer paradigms and metrics are evolving to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adrenergic Agonists
An adrenergic agonist is a drug that stimulates a response from the adrenergic receptors. The five main categories of adrenergic receptors are: α1, α2, β1, β2, and β3, although there are more subtypes, and agonists vary in specificity between these receptors, and may be classified respectively. However, there are also other mechanisms of adrenergic agonism. Epinephrine and norepinephrine are endogenous and broad-spectrum. More selective agonists are more useful in pharmacology. An ' agent is a drug, or other substance, which has effects similar to, or the same as, epinephrine (adrenaline). Thus, it is a kind of sympathomimetic agent. Alternatively, it may refer to something which is susceptible to epinephrine, or similar substances, such as a biological receptor (specifically, the adrenergic receptors). Receptors Directly acting adrenergic agonists act on adrenergic receptors. All adrenergic receptors are G-protein coupled, activating signal transduction pathways. The G-prote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intraocular Pressure
Intraocular pressure (IOP) is the fluid pressure inside the eye. Tonometry is the method eye care professionals use to determine this. IOP is an important aspect in the evaluation of patients at risk of glaucoma. Most tonometers are calibrated to measure pressure in millimeters of mercury (mmHg). Physiology Intraocular pressure is determined by the production and drainage of aqueous humour by the ciliary body and its drainage via the trabecular meshwork and uveoscleral outflow. The reason for this is because the vitreous humour in the posterior segment has a relatively fixed volume and thus does not affect intraocular pressure regulation. An important quantitative relationship (Goldmann's equation) is as follows: :P_o = \frac + P_v Where: * P_o is the IOP in millimeters of mercury (mmHg) * F the rate of aqueous humour formation in microliters per minute (μL/min) * U the resorption of aqueous humour through the uveoscleral route (μL/min) * C is the facility of outflow in m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
