U-373 MG glioblastoma and IMR-32 neuroblastoma cell lines express the dopamine and vesicular monoamine transporters.
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, [3H]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 KD of 2.95 and 0.42 nM and a Bmax of 6.4 and 0.83 fmol/mg protein for U-373 MG and IMR-32 cells, respectively. The low-affinity sites exhibited a KD of 144 and 251 nM and a Bmax of 37.5 and 119 fmol/mg protein for the same cells, respectively. The high-affinity binding of both types of cells probably represents the "classic" 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 +/- 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.
Koutsilieri
E
E
Department of Psychiatry, Julius Maximilians University, Würzburg, Germany.
Kornhuber
J
J
Degen
H J
HJ
Lesch
K P
KP
Sopper
S
S
ter Meulen
V
V
Riederer
P
P
D000818:Animals; D001932:Brain Neoplasms / Q000378:metabolism*; D002352:Carrier Proteins / Q000096:biosynthesis*; D002460:Cell Line; D004298:Dopamine / Q000378:metabolism; D050483:Dopamine Plasma Membrane Transport Proteins; D005909:Glioblastoma / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000096:biosynthesis*; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D009447:Neuroblastoma / Q000378:metabolism*; D009479:Neuropeptides; D010879:Piperazines / Q000378:metabolism / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D050492:Vesicular Biogenic Amine Transport Proteins
D002352:Carrier Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; D010879:Piperazines; D012333:RNA, Messenger; D050492:Vesicular Biogenic Amine Transport Proteins; C044630:1-(2 (diphenylmethoxy)ethyl)-4-(3-phenylpropyl)piperazine; D004298:Dopamine