U-373 MG glioblastoma and IMR-32 neuroblastoma cell lines express the dopamine and vesicular monoamine transporters
✍ Scribed by E. Koutsilieri; J. Kornhuber; H.-J. Degen; K.P. Lesch; S. Sopper; V. ter Meulen; P. Riederer
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 624 KB
- Volume
- 45
- Category
- Article
- ISSN
- 0360-4012
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✦ Synopsis
The U-373 MG glioblastoma and the IMR-32 neuroblastoma cell lines were found to express the dopamine (DA) and vesicular monoamine transporters, using reverse transcriptase-polymerase chain reaction (RT-PCR). To further characterize the DA transporter, r3H]GBR-12935 binding and [3H]DA uptake studies were performed. Specific binding of [3H]GBR-12935 to U-373 MG and IMR-32 cells is saturable as saturation experiments indicated. Scatchard analysis revealed two binding sites on U-373 MG as well as on IMR-32 cells. The high-affinity sites exhibited a K, of 2.95 and 0.42 nM and a B, , of 6.4 and 0.83 fmoVmg protein for U-373 MG and IMR-32 cells, respectively. The low-affinity sites exhibited a K, of 144 and 251 nM and a B,,, of 37.5 and 119 fmoVmg protein for the same cells, respectively. The high-affinity binding of both types of cells probably represents the "cla~sic'~ DA uptake site identified in other studies from human and rat striatal membranes or synaptosomes, while the low-affinity binding may represent a mazindol-insensitive binding site (the "piperazine acceptor site"). [3H]DA uptake was 0.55 & 0.16 and 1.08 k 0.33 pmol/mg protein for U-373 MG and IMR-32 cells, respectively. Since the DA transporter has been implicated as an important site for drugs and toxins, the above-mentioned cell lines may be a useful tool in the study of the mechanism of action of DA transporter modulating substances.