Obrenovitch T P, Clayton C B, Strong A J
J Cereb Blood Flow Metab. 1987 Jun;7(3):356-65. doi: 10.1038/jcbfm.1987.73.
A double-radionuclide autoradiographic method has been assessed for sequential determinations of local CBF (LCBF). It is based on two successive intravascular injections of N-isopropyl-p-iodoamphetamine (IMP) labelled with different radionuclides, whose concentrations can later be differentiated in the same tissue section using double-radionuclide autoradiography. Previous studies suggested that the distribution of IMP, up to 30 min after its administration, still represents LCBFs. Our data indicate that, provided the tracer is injected directly into the left ventricle, there is little back diffusion from normal brain to blood under physiological conditions for at least 35 min following the tracer injection and an injection of unlabelled IMP, in a dose larger than that used for blood flow determination, does not displace any labelled IMP previously taken up by the brain, nor does it displace any labelled IMP previously accumulated in the lung that would lead to secondary brain uptake. On the basis of these results, we conclude that sequential autoradiographic determinations of LCBF using IMP labelled with different radionuclides is possible. This is a promising experimental method for the simultaneous investigation of changes in LCBF in several CNS structures.
一种双放射性核素放射自显影方法已被评估用于连续测定局部脑血流量（LCBF）。它基于两次连续的血管内注射用不同放射性核素标记的N-异丙基-p-碘安非他明（IMP），随后可使用双放射性核素放射自显影在同一组织切片中区分其浓度。先前的研究表明，IMP给药后长达30分钟的分布仍代表LCBF。我们的数据表明，倘若将示踪剂直接注入左心室，在生理条件下，示踪剂注射后至少35分钟内，正常脑组织向血液的反向扩散极少，并且注射未标记的IMP（剂量大于用于血流测定的剂量）不会置换先前被脑摄取的任何标记IMP，也不会置换先前在肺中积累的任何会导致脑二次摄取的标记IMP。基于这些结果，我们得出结论，使用不同放射性核素标记的IMP进行连续放射自显影测定LCBF是可行的。这是一种用于同时研究多个中枢神经系统结构中LCBF变化的有前景的实验方法。
