的敏感性[11 c]苯肾上腺素动力学单胺氧化酶活动正常的人类心脏。

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Raffel DM、小Corbett del Rosario RB, Mukhopadhyay SK, Gildersleeve DL,玫瑰P,维兰德DM

的敏感性[11 c]苯肾上腺素动力学单胺氧化酶活动正常的人类心脏。

J诊断。1999年2月,40 (2):232 - 8。

PubMed ID

10025828 (在PubMed

]

文摘

去甲肾上腺素与11 c标记作为一种放射性示踪剂开发心脏交感神经成像研究的宠物。去甲肾上腺素的结构模拟,(-)- c[11]苯肾上腺素(苯酚的)被运送到心脏交感神经神经去甲肾上腺素转运体静脉曲张,存储在囊泡。苯酚的也是一个衬底对单胺氧化酶(MAO)。本研究的目的是评估毛神经元活动的重要性在苯酚的动力学在正常人类的心脏。毛的苯酚的代谢抑制在示踪级别用氘原子的两个氢原子在α碳侧链的位置产生MAO-resistant模拟D2-PHEN。方法:宠物的苯酚的研究和D2-PHEN配对进行六个正常志愿者。血流动力学和心电图描记的反应都是被监控的。完整的放射性示踪剂和放射性标记的代谢物浓度测定在静脉采集的样本在60分钟动态宠物研究。心肌示踪剂的保留区域保留指数量化。示踪剂流出6 - 50分钟后示踪剂注入是适合一个指数的过程获得冲刷半场左心室区域。 RESULTS: Although initial heart uptake of the two tracers was similar, D2-PHEN cleared from the heart 2.6 times more slowly than PHEN (mean half-time 155+/-52 versus 55+/-10 min, respectively; P < 0.01). Correspondingly, heart retention of D2-PHEN at 40-60 min after tracer injection was higher than PHEN (mean retention indices 0.086+/-0.018 versus 0.066+/-0.011 mL blood/ min/mL tissue, respectively; P < 0.003). CONCLUSION: Efflux of radioactivity from normal human heart after uptake of PHEN is primarily due to metabolism of the tracer by neuronal MAO. Related mechanistic studies in the isolated rat heart indicate that vesicular storage of PHEN protects the tracer from rapid metabolism by neuronal MAO, suggesting that MAO metabolism of PHEN leaking from storage vesicles leads to the gradual loss of PHEN from the neurons. Thus, although MAO metabolism influences the rate of clearance of PHEN from the neurons, MAO metabolism is not the rate-determining step in the observed efflux rate under normal conditions. Rather, the rate at which PHEN leaks from storage vesicles is likely to be the rate-limiting step in the observed efflux rate.

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药物酶

药物	酶	类	生物	药理作用	行动
苯肾上腺素	胺氧化酶(flavin-containing)	蛋白质	人类	未知的	底物	细节