Autoreceptor
An autoreceptor is a type of Receptor (biochemistry), receptor located in the cell membrane, membranes of neuron, nerve cells. It serves as part of a negative feedback loop in signal transduction. It is only sensitive to the neurotransmitters or hormones released by the neuron on which the autoreceptor sits. Similarly, a heteroreceptor is sensitive to neurotransmitters and hormones that are not released by the cell on which it sits. A given receptor can act as either an autoreceptor or a heteroreceptor, depending upon the type of transmitter released by the cell on which it is embedded. Autoreceptors may be located in any part of the cell membrane: in the dendrites, the perikaryon, cell body, the axon, or the axon terminals. Canonically, a presynaptic neuron releases a neurotransmitter across a synaptic cleft to be detected by the receptors on a postsynaptic neuron. Autoreceptors on the presynaptic neuron will also detect this neurotransmitter and often function to control intern ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Heteroreceptor
A heteroreceptor is a Receptor (biochemistry), receptor located in the cell membrane of a neuron, regulating the synthesis and/or the release of mediators other than its own Ligand (biochemistry), ligand. Heteroreceptors play a crucial role in modulating neurotransmitter systems and are often targets for therapeutic drugs. By influencing the activity of other neurotransmitters, the receptors contribute to the complex regulation of neural communication and have been implicated in various physiological and pathological processes. Heteroreceptors may be located in any part of the Neuron including the Dendrite, dendrites, the Perikaryon, cell body, the axon, or the Axon terminal, axon terminals. Heteroreceptors respond to Neurotransmitter, neurotransmitters, Neuromodulator, neuromodulators, or Neurohormone, neurohormones released from adjacent neurons or cells; they are opposite to Autoreceptor, autoreceptors, which are sensitive only to neurotransmitters or hormones released by the ce ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Axon Terminal
Axon terminals (also called terminal boutons, synaptic boutons, end-feet, or presynaptic terminals) are distal terminations of the branches of an axon. An axon, also called a nerve fiber, is a long, slender projection of a Neuron, nerve cell that conducts electrical impulses called action potentials away from the neuron's cell body to transmit those impulses to other neurons, muscle cells, or glands. Most presynaptic terminals in the central nervous system are formed along the axons (en passant boutons), not at their ends (terminal boutons). Functionally, the axon terminal converts an electrical signal into a chemical signal. When an action potential arrives at an axon terminal (A), neurotransmitter, the neurotransmitter is released and diffuses across the synaptic cleft. If the postsynaptic cell (B) is also a neuron, Neurotransmitter receptor, neurotransmitter receptors generate a small electrical current that changes the postsynaptic potential. If the postsynaptic cell (B) is ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Histamine
Histamine is an organic nitrogenous compound involved in local immune responses communication, as well as regulating physiological functions in the gut and acting as a neurotransmitter for the brain, spinal cord, and uterus. Discovered in 1910, histamine has been considered a local hormone ( autocoid) because it is produced without involvement of the classic endocrine glands; however, in recent years, histamine has been recognized as a central neurotransmitter. Histamine is involved in the inflammatory response and has a central role as a mediator of itching. As part of an immune response to foreign pathogens, histamine is produced by basophils and by mast cells found in nearby connective tissues. Histamine increases the permeability of the capillaries to white blood cells and some proteins, to allow them to engage pathogens in the infected tissues. It consists of an imidazole ring attached to an ethylamine chain; under physiological conditions, the amino grou ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Receptor (biochemistry)
In biochemistry and pharmacology, receptors are chemical structures, composed of protein, that receive and Signal_transduction, transduce signals that may be integrated into biological systems. These signals are typically chemical messengers which bind to a receptor and produce physiological responses, such as a change in the electrophysiology, electrical activity of a cell. For example, GABA, an inhibitory neurotransmitter, inhibits electrical activity of neurons by binding to GABAA receptor, GABA receptors. There are three main ways the action of the receptor can be classified: relay of signal, amplification, or integration. Relaying sends the signal onward, amplification increases the effect of a single ligand (biochemistry), ligand, and integration allows the signal to be incorporated into another biochemical pathway. Receptor proteins can be classified by their location. Cell surface receptors, also known as transmembrane receptors, include ligand-gated ion channels, G prote ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Triptan
Triptans are a family of tryptamine-based medication, drugs used as abortive medication in the treatment of migraines and cluster headaches. This drug class was first commercially introduced in the 1990s. While effective at treating individual headaches, they do not provide preventive treatment and are not considered a cure. They are not effective for the treatment of tension headache, tension–type headache, except in persons who also experience migraines. Triptans do not relieve other kinds of pain. The drugs of this class act as agonists for serotonin 5-HT1B receptor, 5-HT1B and 5-HT1D receptor, 5-HT1D receptors at blood vessels and nerve endings in the brain. The first clinically available triptan was sumatriptan, which has been marketed since 1991. Triptans have largely replaced ergotamines, an older class of medications used to relieve migraine and cluster headaches. Medical uses Migraine Triptans are used for the treatment of severe migraine attacks or those that do no ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Clonidine
Clonidine, sold under the brand name Catapres among others, is an α2A-adrenergic receptor agonist medication used to treat high blood pressure, attention deficit hyperactivity disorder (ADHD), drug withdrawal (e.g., alcohol, opioids, or nicotine), menopausal flushing, diarrhea, spasticity, and certain pain conditions. The drug is often prescribed off-label for tics. It is used orally (by mouth), by injection, or as a transdermal skin patch. Onset of action is typically within an hour with the effects on blood pressure lasting for up to eight hours. Common side effects include dry mouth, dizziness, headaches, hypotension, and sleepiness. Severe side effects may include hallucinations, heart arrhythmias, and confusion. If rapidly stopped, withdrawal effects may occur, such as a dangerous rise in blood pressure. Use during pregnancy or breastfeeding is not recommended. Clonidine lowers blood pressure by stimulating α2-adrenergic receptors in the brain, which results i ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Hypertension
Hypertension, also known as high blood pressure, is a Chronic condition, long-term Disease, medical condition in which the blood pressure in the artery, arteries is persistently elevated. High blood pressure usually does not cause symptoms itself. It is, however, a major risk factor for stroke, coronary artery disease, heart failure, atrial fibrillation, peripheral arterial disease, vision loss, chronic kidney disease, and dementia. Hypertension is a major cause of premature death worldwide. High blood pressure is classified as essential hypertension, primary (essential) hypertension or secondary hypertension. About 90–95% of cases are primary, defined as high blood pressure due to non-specific lifestyle and Genetics, genetic factors. Lifestyle factors that increase the risk include excess salt in the diet, overweight, excess body weight, smoking, physical inactivity and Alcohol (drug), alcohol use. The remaining 5–10% of cases are categorized as secondary hypertension, d ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Tizanidine
Tizanidine, sold under the brand name Zanaflex among others, is an alpha-2 (α2) adrenergic receptor agonist, similar to clonidine, that is used to treat muscle spasticity due to spinal cord injury, multiple sclerosis, and spastic cerebral palsy. Effectiveness appears similar to baclofen or diazepam. It is taken by mouth. Common side effects of tizanidine include dry mouth, sleepiness, weakness, and dizziness. Serious side effects may include low blood pressure, liver problems, psychosis, and QT prolongation. It is unclear if use in pregnancy and breastfeeding is safe. It is an α2-adrenergic agonist, but how it works is not entirely clear. Tizanidine was approved for medical use in the United States in 1996. It is available as a generic medication. In 2022, it was the 94th most commonly prescribed medication in the United States, with more than 6million prescriptions. Medical uses Tizanidine has been found to be as effective as other antispasmodic drugs and i ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Buspirone
Buspirone, sold under the brand name Buspar among others, is an anxiolytic, a medication primarily used to treat anxiety disorders, particularly generalized anxiety disorder (GAD). It is a serotonin 5-HT1A receptor, 5-HT1A receptor partial agonist, increasing action at serotonin receptors in the brain. It is taken orally and takes two to six weeks to be fully effective. Common side effects of buspirone include nausea, headaches, dizziness, and difficulty concentrating. Serious side effects may include movement disorders, serotonin syndrome, and seizures. Its use in pregnancy appears to be safe but has not been well studied, and use during breastfeeding has not been well studied either. Buspirone was developed in 1968 and approved for medical use in the United States in 1986. It is available as a generic medication. In 2022, it was the 54th most commonly prescribed medication in the United States, with more than 12million prescriptions. Medical uses Anxiety Buspirone is used ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Lasmiditan
Lasmiditan, sold under the brand name Reyvow, is a medication used for the acute (active but short-term) treatment of migraine with or without aura (a sensory phenomenon or visual disturbance) in adults. It is not useful for prevention. It is taken by mouth. Common side effects include sleepiness, dizziness, tiredness, and numbness. Lasmiditan was approved in the United States in October 2019 and became available in February 2020. It was developed by Eli Lilly. The U.S. Food and Drug Administration (FDA) considers it to be a first-in-class medication. Pharmacology Mechanism of action Lasmiditan is a serotonin receptor agonist that, like the unsuccessful LY-334,370, selectively binds to the 5-HT1F receptor subtype. A number of triptans have been shown to act on this subtype as well, but only after their affinity for 5-HT1B and 5-HT1D has been made responsible for their anti-migraine activity. The lack of affinity for these receptors might result in fewer side effects re ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Ergot
Ergot ( ) or ergot fungi refers to a group of fungi of the genus ''Claviceps''. The most prominent member of this group is '' Claviceps purpurea'' ("rye ergot fungus"). This fungus grows on rye and related plants, and produces alkaloids that can cause ergotism in humans and other mammals who consume grains contaminated with its fruiting structure (called ''ergot sclerotium''). ''Claviceps'' includes about 50 known species, mostly in the tropical regions. Economically significant species include ''C. purpurea'' (parasitic on grasses and cereals), ''C. fusiformis'' (on pearl millet, buffel grass), '' C. paspali'' (on dallis grass), ''C. africana'' (on sorghum) and ''C. lutea'' (on paspalum). ''C. purpurea'' most commonly affects outcrossing species such as rye (its most common host), as well as triticale, wheat and barley. It affects oats only rarely. ''C. purpurea'' has at least three races or varieties, which differ in their host specificity: *G1 – land grasses of op ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Pitolisant
Pitolisant, sold under the brand name Wakix among others, is a medication used for the treatment of excessive daytime sleepiness in adults with narcolepsy. It is an inverse agonist of the histamine H3 receptor. It represents the first commercially available medication in its class, so that the U.S. Food and Drug Administration (FDA) declares it a first-in-class medication. Pitolisant enhances the activity of histaminergic neurons in the brain that function to improve a person's wakefulness. It was approved by the European Medicines Agency (EMA) in March 2016 for narcolepsy with or without cataplexy, and for excessive daytime sleepiness by the FDA in August 2019. The most common side effects include difficulty sleeping, nausea, and feeling worried. Medical uses Pitolisant is indicated in adults for the treatment of narcolepsy. Text was copied from this source which is copyright European Medicines Agency. Reproduction is authorized provided the source is acknowledged. Narcol ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |