کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2531509 1558929 2015 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
In vitro and ex vivo characterization of (−)-TZ659 as a ligand for imaging the vesicular acetylcholine transporter
موضوعات مرتبط
علوم زیستی و بیوفناوری علم عصب شناسی علوم اعصاب سلولی و مولکولی
پیش نمایش صفحه اول مقاله
In vitro and ex vivo characterization of (−)-TZ659 as a ligand for imaging the vesicular acetylcholine transporter
چکیده انگلیسی

The loss of cholinergic neurons and synapses relates to the severity of dementia in several neurodegenerative pathologies; and the vesicular acetylcholine transporter (VAChT) provides a reliable biomarker of cholinergic function. We recently characterized and 11C-labeled a new VAChT inhibitor, (−)-TZ659. Here we report the in vitro and ex vivo characterization of (−)-TZ659. A stably transfected PC12A123.7 cell line which expresses human VAChT (hVAChT) was used for the in vitro binding characterization of (−)-[3H]TZ659. A saturated binding curve was obtained with Kd=1.97±0.30 nM and Bmax=3240±145.9 fmol/mg protein. In comparison, a PC12A123.7 cell line that expresses mutant hVAChT showed decreased binding affinity (Kd=15.94±0.28 nM). Competitive binding assays using a panel of other CNS ligands showed no inhibition of (−)-[3H]TZ659 binding. On the other hand, binding inhibitions were observed only using VAChT inhibitors (Ki=0.20–31.35 nM). An in vitro assay using rat brain homogenates showed that (−)-[3H]TZ659 had higher binding in striatum than in cerebellum, with a target: non-target ratio>3.46. Even higher ex vivo striatum-to-cerebellum ratios (9.56±1.11) were observed using filtered homogenates of brain tissue after rats were injected intravenously with (−)-[11C]TZ659. Ex vivo autoradiography of (−)-[11C]TZ659 confirmed high striatal uptake, with a consistently high striatum-to-cerebellum ratio (2.99±0.44). In conclusion, (−)-TZ659 demonstrated high potency and good specificity for VAChT in vitro and in vivo. These data suggest that (−)-[11C]TZ659 may be a promising PET tracer to image VAChT in the brain.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: European Journal of Pharmacology - Volume 752, 5 April 2015, Pages 18–25
نویسندگان
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