Myocardial kinetics of carbon-11-epinephrine in the isolated working rat heart.
Myocardial kinetics of carbon-11-epinephrine in the isolated working rat heart.
复制标题
DOI：
--
复制
发表时间：
1997-05
期刊：
影响因子：
--
通讯作者：
Ngoc Nguyen;T. DeGrado;Pulak K. Chakraborty;Donald M. Wieland;Markus Schwaiger
中科院分区：
文献类型：
--
作者：
Ngoc Nguyen;T. DeGrado;Pulak K. Chakraborty;Donald M. Wieland;Markus Schwaiger
在离体大鼠心脏模型中研究了EPI的动力学，以评价11 C-肾上腺素（EPI）作为评价心脏交感神经元功能的放射性示踪剂。方法采用离体大鼠心脏工作模式灌流。碳-11-EPI被添加到灌流液中的冲洗期为20分钟，然后由一个冲洗期为40分钟。在心脏中的放射性进行外部监测和时间-活性曲线记录为时间的函数。在整个研究过程中收集流出物样品，以确定作为完整示踪剂的11 C放射性分数。结果对照心脏的时间-活动曲线显示11 C-EPI被心肌摄取和保留。与对照组相比，地昔帕明对摄取-1的抑制作用（抑制剂）导致心肌摄取和11 C-EPI保留显著降低91%。与对照心脏相比，在洗脱期间向灌注介质中添加11 C-EPI并不影响11 C-EPI的动力学。利血平预处理的大鼠心脏也表现出显着减少示踪剂保留95%，与对照组相比。代谢数据显示，在对照条件下，大鼠心脏摄取的约61%的11 C-EPI被快速代谢和释放。结论~（11）C-EPI可示踪离体大鼠心脏交感神经末梢。通过阻断摄取的11 C-EPI和利血平表明，摄取和储存的11 C-EPI似乎是类似的去甲肾上腺素。然而，重要的代谢途径值得进一步考虑。这些结果表明，11 C-EPI可能是一个合适的放射性标记示踪剂，用于评价心脏的交感囊泡功能的PET。
UNLABELLED The kinetics of EPI were studied in the isolated rat heart model to evaluate 11C-epinephrine (EPI) as a radiotracer for the assessment of sympathetic neuronal function in the heart. METHODS Isolated rat hearts were perfused in a working mode. Carbon-11-EPI was added to the perfusate during wash-in period of 20 min, followed by a washout period of 40 min. Radioactivity in the heart was externally monitored and time-activity curves were recorded as a function of time. Effluent samples were collected throughout each study to determine the fraction of 11C radioactivity as intact tracer. RESULTS Time-activity curves of control hearts showed that 11C-EPI is taken up and retained by the myocardium. Desipramine inhibition (DMI) of uptake-1 resulted in a significant decrease in myocardial uptake and retention of 11C-EPI by 91% compared to controls. Addition of DMI to the perfusion medium during washout did not affect kinetics of 11C-EPI compared to control hearts. Reserpine pretreated rat hearts also showed significant decrease in tracer retention of 95% compared to controls. The metabolic data showed that, in control conditions, about 61% of 11C-EPI taken up by the rat heart is rapidly metabolized and released. CONCLUSION Carbon-11-EPI traces sympathetic nerve terminals in the isolated rat heart. Uptake blockade by DMI and reserpine suggest that uptake and storage of 11C-EPI appear to be similar to that of norepinephrine. However, the prominent metabolic pathway warrants further consideration. These results suggest that 11C-EPI may be a suitable radiolabeled tracer for the evaluation of sympathetic vesicular function of the heart by PET.