HUMAN D-3 DOPAMINE-RECEPTOR IN THE MEDULLOBLASTOMA TE671 CELL-LINE - CROSS-TALK BETWEEN D-1 AND D-3 RECEPTORS

In search of a cell line in which the D-3 dopamine receptor is express ed endogenously, we found that the neuron-derived human medulloblastom a cell line TE671 expresses the human D-3 (hD(3)) and D-1 (hD(1)) rece ptor, but neither the D-2 or D-4 receptors. Exposure of TE671 cells to the D-3 agonist 7-OH-DPAT (DPAT), or to the D-1 agonist SKF-38393 (SK F) increased the expression of hD(3) or hD1 mRNA, respectively. Moreov er, whereas DPAT had no effect on hD(1) mRNA levels, stimulating the c ells with SKF caused an increase in both hD(1) and hD(3) transcript le vels. These results suggest (1) that following ligand stimulation, hD( 3) and hD(1) receptors are upregulated to enhance their own receptor e xpression, and (ii) that upregulation of hD(1) receptor transcripts le ads to a stimulation of the hD(3) dopamine receptor transcripts. (C) 1 998 Federation of European Biochemical Societies.