An antibody to dopamine D2 receptor inhibits dopamine antagonist and agonist binding to dopamine D2 receptor cDNA transfected mouse fibroblast cells.
A polyclonal antibody to dopamine D2 receptor (D2-receptor) has been used to examine the immuno-inhibition in the binding of a D2 antagonist, [3H]YM09151-2 and an agonist, PPHT-fluorescein to dopamine receptor DNA transfected mouse fibroblast cells. The specific activity of the [3H]YM09151-2 binding to transfected (Ltk-RGB) cells is 4-5 fold higher than untransfected (Ltk-) cells. The antibody is able to inhibit the [3H]YM09151-2 binding to the cell membranes from Ltk-RGB cells (Bmax 110.56 +/- 5.26 and 76.20 +/- 5.18 fmoles/mg protein in the presence of preimmune and immune sera, respectively, with no change in the Kd). The flow cytometric analysis of the PPHT-fluorescein labeled Ltk- and Ltk-RGB cells indicated that ligand specific fluorescence is associated only with small Ltk-RGB cells (second peak) and autofluorescence with large cells (first peak). Preincubation of the Ltk-RGB cells with antibody, reduced the fluorescence intensity of the PPHT-fluorescein by 20-25% without changing the auto-fluorescence. These results suggest that peptide antibody recognize D2-receptor in both membranes and in intact cells and interact at or near the ligand binding site of the receptor.
Laboratory of Neurosciences, Pennington Biomedical Research Center, Baton Rouge, LA 70808.
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Farooqui
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Prasad
D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000918:Antibody Specificity; D001549:Benzamides / Q000378:metabolism; D002478:Cells, Cultured; D015259:Dopamine Agents / Q000378:metabolism*; D018492:Dopamine Antagonists; D005347:Fibroblasts / Q000378:metabolism*; D005434:Flow Cytometry; D005452:Fluoresceins / Q000378:metabolism; D051379:Mice; D017448:Receptors, Dopamine D2 / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000276:immunology / Q000378:metabolism; D014162:Transfection
C077797:2-(N-phenylethyl-N-propyl)amino-5-hydroxytetralin fluorescein; D000906:Antibodies; D001549:Benzamides; D015259:Dopamine Agents; D018492:Dopamine Antagonists; D005452:Fluoresceins; D017448:Receptors, Dopamine D2; D011994:Recombinant Proteins; C030265:nemonapride