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Adrenergic Receptors
The adrenergic receptors or adrenoceptors are a class of G protein-coupled receptors that are targets of many catecholamines like norepinephrine (noradrenaline) and epinephrine (adrenaline) produced by the body, but also many medications like beta blockers, beta-2 (β2) agonists and alpha-2 (α2) agonists, which are used to treat high blood pressure and asthma, for example. Many cells have these receptors, and the binding of a catecholamine to the receptor will generally stimulate the sympathetic nervous system (SNS). The SNS is responsible for the fight-or-flight response, which is triggered by experiences such as exercise or fear-causing situations. This response dilates pupils, increases heart rate, mobilizes energy, and diverts blood flow from non-essential organs to skeletal muscle. These effects together tend to increase physical performance momentarily. History By the turn of the 19th century, it was agreed that the stimulation of sympathetic nerves could cause different ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
100-AdrenergicReceptors-2rh1
1 (one, unit, unity) is a number representing a single or the only entity. 1 is also a numerical digit and represents a single unit of counting or measurement. For example, a line segment of ''unit length'' is a line segment of length 1. In conventions of sign where zero is considered neither positive nor negative, 1 is the first and smallest positive integer. It is also sometimes considered the first of the infinite sequence of natural numbers, followed by 2, although by other definitions 1 is the second natural number, following 0. The fundamental mathematical property of 1 is to be a multiplicative identity, meaning that any number multiplied by 1 equals the same number. Most if not all properties of 1 can be deduced from this. In advanced mathematics, a multiplicative identity is often denoted 1, even if it is not a number. 1 is by convention not considered a prime number; this was not universally accepted until the mid-20th century. Additionally, 1 is the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norepinephrine
Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as both a hormone and neurotransmitter. The name "noradrenaline" (from Latin '' ad'', "near", and '' ren'', "kidney") is more commonly used in the United Kingdom, whereas "norepinephrine" (from Ancient Greek ἐπῐ́ (''epí''), "upon", and νεφρός (''nephrós''), "kidney") is usually preferred in the United States. "Norepinephrine" is also the international nonproprietary name given to the drug. Regardless of which name is used for the substance itself, parts of the body that produce or are affected by it are referred to as noradrenergic. The general function of norepinephrine is to mobilize the brain and body for action. Norepinephrine release is lowest during sleep, rises during wakefulness, and reaches much higher levels during situations of stress or danger, in the so-called fight-or-flight response. In the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agonist
An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the agonist, while an inverse agonist causes an action opposite to that of the agonist. Etymology From the Greek αγωνιστής (agōnistēs), contestant; champion; rival < αγων (agōn), contest, combat; exertion, struggle < αγω (agō), I lead, lead towards, conduct; drive Types of agonists can be activated by either endogenous agonists (such as |
Adenylyl Cyclase
Adenylate cyclase (EC 4.6.1.1, also commonly known as adenyl cyclase and adenylyl cyclase, abbreviated AC) is an enzyme with systematic name ATP diphosphate-lyase (cyclizing; 3′,5′-cyclic-AMP-forming). It catalyzes the following reaction: :ATP = 3′,5′-cyclic AMP + diphosphate It has key regulatory roles in essentially all cells. It is the most polyphyletic known enzyme: six distinct classes have been described, all catalyzing the same reaction but representing unrelated gene families with no known sequence or structural homology. The best known class of adenylyl cyclases is class III or AC-III (Roman numerals are used for classes). AC-III occurs widely in eukaryotes and has important roles in many human tissues. All classes of adenylyl cyclase catalyse the conversion of adenosine triphosphate (ATP) to 3',5'-cyclic AMP (cAMP) and pyrophosphate.Magnesium ions are generally required and appear to be closely involved in the enzymatic mechanism. The cAMP produced by AC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gs Protein
The Gs alpha subunit (Gαs, Gsα) is a subunit of the heterotrimeric G protein Gs that stimulates the cAMP-dependent pathway by activating adenylyl cyclase. Gsα is a GTPase that functions as a cellular signaling protein. Gsα is the founding member of one of the four families of heterotrimeric G proteins, defined by the alpha subunits they contain: the Gαs family, Gαi/Gαo family, Gαq family, and Gα12/Gα13 family. The Gs-family has only two members: the other member is Golf, named for its predominant expression in the olfactory system. In humans, Gsα is encoded by the GNAS complex locus, while Golfα is encoded by the GNAL gene. Function The general function of Gs is to activate intracellular signaling pathways in response to activation of cell surface G protein-coupled receptors (GPCRs). GPCRs function as part of a three-component system of receptor-transducer-effector. The transducer in this system is a heterotrimeric G protein, composed of three subunits: a Gα ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta-3 Adrenergic Receptor
The beta-3 adrenergic receptor (β3-adrenoceptor), also known as ADRB3, is a beta-adrenergic receptor, and also denotes the human gene encoding it. Function Actions of the β3 receptor include *Enhancement of lipolysis in adipose tissue. *Thermogenesis in skeletal muscle Page 163 It is located mainly in adipose tissue and is involved in the regulation of lipolysis and thermogenesis. Some β3 agonists have demonstrated antistress effects in animal studies, suggesting it also has a role in the central nervous system (CNS). β3 receptors are found in the gallbladder, urinary bladder, and in brown adipose tissue. Their role in gallbladder physiology is unknown, but they are thought to play a role in lipolysis and thermogenesis in brown fat. In the urinary bladder it is thought to cause relaxation of the bladder and prevention of urination. Mechanism of action Beta adrenergic receptors are involved in the epinephrine- and norepinephrine-induced activation of adenylate cyclase th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta-1 Adrenergic Receptor
The beta-1 adrenergic receptor (β1 adrenoceptor), also known as ADRB1, is a beta-adrenergic receptor, and also denotes the human gene encoding it. It is a G-protein coupled receptor associated with the Gs heterotrimeric G-protein and is expressed predominantly in cardiac tissue. Receptor Actions Actions of the β1 receptor include: The receptor is also present in the cerebral cortex. Agonists Isoprenaline has higher affinity for β1 than adrenaline, which, in turn, binds with higher affinity than noradrenaline at physiologic concentrations. Selective agonists to the beta-1 receptor are: *Denopamine *Dobutamine (in cardiogenic shock) *Xamoterol (cardiac stimulant) Antagonists ''(Beta blockers)'' β1-selective antagonists include: *Acebutolol (in hypertension, angina pectoris and arrhythmias) *Atenolol (in hypertension, coronary heart disease, arrhythmias and myocardial infarction) * Betaxolol (in hypertension and glaucoma) *Bisoprolol (in hypertension, coronary heart disea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G Protein
G proteins, also known as guanine nucleotide-binding proteins, are a family of proteins that act as molecular switches inside cells, and are involved in transmitting signals from a variety of stimuli outside a cell to its interior. Their activity is regulated by factors that control their ability to bind to and hydrolyze guanosine triphosphate (GTP) to guanosine diphosphate (GDP). When they are bound to GTP, they are 'on', and, when they are bound to GDP, they are 'off'. G proteins belong to the larger group of enzymes called GTPases. There are two classes of G proteins. The first function as monomeric small GTPases (small G-proteins), while the second function as heterotrimeric G protein complexes. The latter class of complexes is made up of '' alpha'' (α), ''beta'' (β) and ''gamma'' (γ) subunits. In addition, the beta and gamma subunits can form a stable dimeric complex referred to as the beta-gamma complex . Heterotrimeric G proteins located within the cell are activ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha-1 Adrenergic Receptor
alpha-1 (α1) adrenergic receptors are G protein-coupled receptors (GPCRs) associated with the Gq heterotrimeric G protein. α1-adrenergic receptors are subdivided into three highly homologous subtypes, i.e., α1A-, α1B-, and α1D-adrenergic receptor subtypes. There is no α1C receptor. At one time, there was a subtype known as α1C, but it was found to be identical to the previously discovered α1A receptor subtype. To avoid confusion, naming was continued with the letter D. Catecholamines like norepinephrine (noradrenaline) and epinephrine (adrenaline) signal through the α1-adrenergic receptors in the central and peripheral nervous systems. The crystal structure of the α1B-adrenergic receptor subtype has been determined in complex with the inverse agonist (+)-cyclazosin. Effects The α1-adrenergic receptor has several general functions in common with the α2-adrenergic receptor, but also has specific effects of its own. α1-receptors primarily mediate smooth muscle cont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raymond Ahlquist
Raymond Perry Ahlquist (July 26, 1914 – April 15, 1983) was an American pharmacist and pharmacologist. He published seminal work in 1948 that divided adrenoceptors into α- and β-adrenoceptor subtypes. This discovery explained the activity of several existing drugs and also laid the ground work for new drugs including the widely prescribed beta blockers. Early life and education Ahlquist was born on July, 26 1914 in Missoula, Montana. Both of his parents came from Sweden. His father was an auditor at the Railway Company Northern Pacific Railway. In 1940, Ahlquist graduated with a Ph.D. degree in pharmacology from the University of Washington in Seattle, the first person to be awarded such a degree from that institution. Career and research Ahlquist spent four years as a faculty member at South Dakota State University in Brookings. In 1944 he became Assistant Professor of Pharmacology at the Medical College of Georgia in Augusta. In 1946 he was appointed Associate Profe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 open ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
