, also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as a hormone and neurotransmitter. The name "noradrenaline," derived from Latin roots meaning "at/alongside the kidneys," is more commonly used in the United Kingdom; in the United States, "norepinephrine," derived from Greek roots having that same meaning, is usually preferred.[1] "Norepinephrine" is also the international nonproprietary name given to the drug.[2] 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.
In the brain, norepinephrine is produced in closely packed brain cell neurons or nuclei that are small yet exert powerful effects on other brain areas. The most important of these nuclei is the locus coeruleus, located in the pons. Outside the brain, norepinephrine is used as a neurotransmitter by sympathetic ganglia located near the spinal cord or in the abdomen, and it is also released directly into the bloodstream by the adrenal glands. Regardless of how and where it is released, norepinephrine acts on target cells by binding to and activating noradrenergic receptors located on the cell surface.
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 brain, norepinephrine increases arousal and alertness, promotes vigilance, enhances formation and retrieval of memory, and focuses attention; it also increases restlessness and anxiety. In the rest of the body, norepinephrine increases heart rate and blood pressure, triggers the release of glucose from energy stores, increases blood flow to skeletal muscle, reduces blood flow to the gastrointestinal system, and inhibits voiding of the bladder and gastrointestinal motility.
A variety of medically important drugs work by altering the actions of norepinephrine systems. Norepinephrine itself is widely used as an injectable drug for the treatment of critically low blood pressure. Beta blockers, which counter some of the effects of norepinephrine, are frequently used to treat glaucoma, migraine, and a range of cardiovascular problems. Alpha blockers, which counter a different set of norepinephrine effects, are used to treat several cardiovascular and psychiatric conditions. Alpha-2 agonists often have a sedating effect, and are commonly used as anesthesia-enhancers in surgery, as well as in treatment of drug or alcohol dependence. Many important psychiatric drugs exert strong effects on norepinephrine systems in the brain, resulting in side-effects that may be helpful or harmful
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، وتسمى أيضا نورادرينالين (NA) أو نورادرينالين، وهو مادة كيميائية عضوية في الأسرة الكاتيكولامينات يعمل في الدماغ والجسم كهرمون وناقل عصبي. اسم "نورادرينالين"، المستمدة من الجذور اللاتينية بمعنى "/جنبا إلى جنب مع الكليتين،" هو أكثر شيوعاً في المملكة المتحدة؛ في الولايات المتحدة، "norepinephrine"، المستمدة من الجذور اليونانية بعد ذلك نفس المعني، يفضل عادة. [1] "norepinephrine" هو أيضا الاسم غير المسجلة الملكية الدولية للمخدرات. [2] بغض النظر عن الاسم الذي يستخدم للمادة نفسها، أجزاء من الجسم التي تنتج أو تتأثر بذلك فيشار إليهما نورادرينيرجيك.في الدماغ، وينتج إفراز في الدماغ عن كثب وجبات الخلية من الخلايا العصبية أو نويات صغيرة بعد ممارسة تأثيرات قوية على مناطق الدماغ الأخرى. وأهم هذه النوى هو كوروليس موضع، يقع في بونس. خارج الدماغ، ويستخدم إفراز عصبي واسطة ganglia متعاطفة مع الواقعة قرب الحبل الشوكي أو في البطن، وأيضا يتم تحريرها مباشرة في مجرى الدم من الغدد الكظرية. بغض النظر عن كيف وأين يتم تحريرها، يعمل إفراز الخلايا الهدف بربط وتفعيل مستقبلات نورادرينيرجيك الموجود على سطح الخلية.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 brain, norepinephrine increases arousal and alertness, promotes vigilance, enhances formation and retrieval of memory, and focuses attention; it also increases restlessness and anxiety. In the rest of the body, norepinephrine increases heart rate and blood pressure, triggers the release of glucose from energy stores, increases blood flow to skeletal muscle, reduces blood flow to the gastrointestinal system, and inhibits voiding of the bladder and gastrointestinal motility.A variety of medically important drugs work by altering the actions of norepinephrine systems. Norepinephrine itself is widely used as an injectable drug for the treatment of critically low blood pressure. Beta blockers, which counter some of the effects of norepinephrine, are frequently used to treat glaucoma, migraine, and a range of cardiovascular problems. Alpha blockers, which counter a different set of norepinephrine effects, are used to treat several cardiovascular and psychiatric conditions. Alpha-2 agonists often have a sedating effect, and are commonly used as anesthesia-enhancers in surgery, as well as in treatment of drug or alcohol dependence. Many important psychiatric drugs exert strong effects on norepinephrine systems in the brain, resulting in side-effects that may be helpful or harmful
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