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catecholamine
catecholamine , any of several compounds occurring naturally in the body that serve as hormones or as neurotransmitters in the sympathetic nervous system . The catecholamines include such compounds as epinephrine , or adrenaline, norepinephrine, and dopamine. They resemble one another chemically in having an aromatic portion (catechol) to which is attached an amine, or nitrogen-containing group. Epinephrine and norepinephrine, which are also hormones, are secreted by the adrenal medulla, and norepinephrine is also secreted by some nerve fibers. These substances prepare the body to meet emergencies such as cold, fatigue, and shock, and norepinephrine is probably a chemical transmitter at nerve synapses. Dopamine is an intermediate in the synthesis of epinephrine. A deficiency of dopamine in the brain is responsible for the symptoms of Parkinson's disease ; medical administration of the drug L-dopa, which is presumed to be converted to dopamine in the brain, relieves the symptoms. Dopamine also appears to play a role in addiction; in a number of different ways, addictive substances cause a rise in the levels of dopamine in the nucleus accumbens, which is believed to be the main reward center in the brain. Epinephrine is used medically to stimulate heartbeat and to treat emphysema, bronchitis, and bronchial asthma and other allergic conditions, as well as in the treatment of the eye disease glaucoma. |
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"catecholamine." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "catecholamine." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1E1-catechol.html "catecholamine." The Columbia Encyclopedia, 6th ed.. 2011. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-catechol.html |
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catecholamine
catecholamine Any of a class of amines that possess a catechol (C6H4(OH)2) ring. Including dopamine, adrenaline, and noradrenaline, they function as neurotransmitters and/or hormones.
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"catecholamine." A Dictionary of Biology. 2004. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "catecholamine." A Dictionary of Biology. 2004. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O6-catecholamine.html "catecholamine." A Dictionary of Biology. 2004. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O6-catecholamine.html |
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catecholamine
catecholamine A dihydroxyphenylalkylamine derivative of the amino acid tyrosine: adrenalin and noradrenalin are two such derivatives. Many catecholamines act as neurotransmitters.
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MICHAEL ALLABY. "catecholamine." A Dictionary of Zoology. 1999. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "catecholamine." A Dictionary of Zoology. 1999. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O8-catecholamine.html MICHAEL ALLABY. "catecholamine." A Dictionary of Zoology. 1999. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O8-catecholamine.html |
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