Peremans K, Audenaert K, Jacobs F, Dumont F, De Vos F, Van De Wiele C, Vandecapelle M, Van Bree H, Verschooten F, Slegers G, Mertens J, Dierckx R
Department of Medical Imaging, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium.
Nucl Med Commun. 2002 Oct;23(10):1019-27. doi: 10.1097/00006231-200210000-00013.
There is increasing interest in mapping receptors in vivo by using functional imaging modalities such as single photon emission tomography (SPET) and positron emission tomography (PET). Since SPET is a more accessible functional imaging modality than PET and, overall, it is more economical, radioligands suitable for this technique are in greater demand. Recently, 123I-5-I-R91150, a radioligand with high selectivity and affinity for 5-HT(2A) receptors in the brain, was introduced for SPET. This study reports on the whole-body distribution and brain uptake of the selective 123I-5-I-R91150 ligand in four normal dogs. The frontal to cerebellar ratio of uptake in time was determined in three dogs. Time-activity curve of venous blood was determined in one dog. Maximal global brain uptake was found at 10-60 min post-injection. Higher brain uptake was noted in the frontal cortical areas compared to the cerebellum. The frontal-cerebellar ratio reached the highest values at 90-180 min. Reversibility and pharmacological selectivity of ligand binding was demonstrated through displacement and blocking studies with the 5-HT(2A) receptor antagonist ketanserin. This study demonstrates that the specific 5-HT(2A) iodinated ligand can be used for imaging and semi-quantification of the 5-HT(2A) receptors in the canine brain in vivo by using SPET.
利用单光子发射断层扫描(SPET)和正电子发射断层扫描(PET)等功能成像方式在体内绘制受体图谱的研究兴趣日益浓厚。由于SPET是一种比PET更容易获得的功能成像方式,而且总体上更经济,因此对适用于该技术的放射性配体的需求更大。最近,一种对大脑中5-HT(2A)受体具有高选择性和亲和力的放射性配体123I-5-I-R91150被引入用于SPET。本研究报告了选择性123I-5-I-R91150配体在四只正常犬体内的全身分布和脑摄取情况。测定了三只犬摄取的额叶与小脑比值随时间的变化。测定了一只犬静脉血的时间-活性曲线。在注射后10-60分钟发现最大全脑摄取量。与小脑相比,额叶皮质区域的脑摄取量更高。额叶-小脑比值在90-180分钟时达到最高值。通过用5-HT(2A)受体拮抗剂酮色林进行置换和阻断研究,证明了配体结合的可逆性和药理选择性。本研究表明,特异性5-HT(2A)碘化配体可通过SPET用于犬脑内5-HT(2A)受体的体内成像和半定量分析。