Institute of Neuroscience and Medicine, INM-2, Forschungszentrum Jülich GmbH, Jülich, 52425, Germany.
Mol Imaging Biol. 2013 Aug;15(4):456-67. doi: 10.1007/s11307-013-0621-3. Epub 2013 Mar 1.
While the selective 5-hydroxytryptamine type 2a receptor (5-HT2AR) radiotracer [18F]altanserin is well established in humans, the present study evaluated its suitability for quantifying cerebral 5-HT2ARs with positron emission tomography (PET) in albino rats.
Ten Sprague Dawley rats underwent 180 min PET scans with arterial blood sampling. Reference tissue methods were evaluated on the basis of invasive kinetic models with metabolite-corrected arterial input functions. In vivo 5-HT2AR quantification with PET was validated by in vitro autoradiographic saturation experiments in the same animals.
Overall brain uptake of [18F]altanserin was reliably quantified by invasive and non-invasive models with the cerebellum as reference region shown by linear correlation of outcome parameters. Unlike in humans, no lipophilic metabolites occurred so that brain activity derived solely from parent compound. PET data correlated very well with in vitro autoradiographic data of the same animals.
[18F]Altanserin PET is a reliable tool for in vivo quantification of 5-HT2AR availability in albino rats. Models based on both blood input and reference tissue describe radiotracer kinetics adequately. Low cerebral tracer uptake might, however, cause restrictions in experimental usage.
虽然选择性 5-羟色胺 2A 受体（5-HT2AR）放射性配体 [18F]altanserin 在人体中得到了很好的应用，但本研究旨在评估其在白化大鼠正电子发射断层扫描（PET）中定量测定脑 5-HT2AR 的适用性。
十只 Sprague Dawley 大鼠进行了 180 分钟的 PET 扫描和动脉采血。根据带有代谢物校正的动脉输入函数的侵入性动力学模型评估参考组织方法。在相同动物的体外放射性自显影饱和实验中验证了 PET 对 5-HT2AR 的体内定量。
通过侵入性和非侵入性模型，以小脑作为参考区域，可靠地定量了 [18F]altanserin 的整体脑摄取，通过线性相关的结果参数显示。与人类不同的是，没有脂溶性代谢物，因此脑活性仅源自母体化合物。PET 数据与同一动物的体外放射性自显影数据非常吻合。
[18F]Altanserin PET 是一种可靠的工具，可用于在白化大鼠体内定量测定 5-HT2AR 的可用性。基于血液输入和参考组织的模型可以充分描述放射性示踪剂的动力学。然而，低脑示踪剂摄取可能会限制实验的使用。
