儿茶酚胺
兒茶酚胺(英語:Catecholamine)是具有兒茶酚核的(苯乙)胺類化合物的統稱,是由腎上腺產生的一類應激擬交感「鬥或逃」(Fight or Flight)激素。最重要的兒茶酚胺是腎上腺素(Epinephrine)、去甲腎上腺素(正腎上腺素)和多巴胺(Dopamine),均是從苯丙氨酸和酪氨酸合成。去甲腎上腺素在中樞神經系統內分布廣泛,含量較多,而腎上腺素含量則較少。多巴胺主要集中在錐體外系部位,也是一種神經介質。它們是重要的典型的腎上腺素受體激動劑。不少精神興奮劑也是兒茶酚胺的類似物。
兒茶酚胺有去甲腎上腺素(NAd)、腎上腺素(Ad)、多巴胺(DA),過多的兒茶酚胺分泌可能導致高血壓和心肌梗塞;而低水平的兒茶酚胺可能引起低血壓、心肌缺血等。在臨床上兒茶酚胺常被用來治療神經源性、心源性、中毒源性休克早期,但過多剂量可能導致局部組織壞死或者腎衰竭。
参考文献
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The highest level of brain CYP2D activity was found in the substantia nigra ... The in vitro and in vivo studies have shown the contribution of the alternative CYP2D-mediated dopamine synthesis to the concentration of this neurotransmitter although the classic biosynthetic route to dopamine from tyrosine is active. ... Tyramine levels are especially high in the basal ganglia and limbic system, which are thought to be related to individual behavior and emotion (Yu et al., 2003c). ... Rat CYP2D isoforms (2D2/2D4/2D18) are less efficient than human CYP2D6 for the generation of dopamine from p-tyramine. The Km values of the CYP2D isoforms are as follows: CYP2D6 (87–121 μm) ≈ CYP2D2 ≈ CYP2D18 > CYP2D4 (256 μm) for m-tyramine and CYP2D4 (433 μm) > CYP2D2 ≈ CYP2D6 > CYP2D18 (688 μm) for p-tyramine
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