title: Expression of functional D2 dopamine receptors following differentiation of Y-79 human retinoblastoma cells.
abstract: Y-79 human retinoblastoma cells grown in serum-free medium in monolayer culture have previously been shown to undergo differentiation in response to dibutyryl cyclic AMP (Bt2cAMP). We report here that Y-79 cells treated in this manner also express very high levels of functional D2 dopamine receptors. In control Y-79 cells, cultured in suspension, D2 dopamine receptors, quantified via saturation analysis with the D2 antagonist [3H]methylspiperone, are expressed at a level of approximately 3 fmol/10(6) cells (approximately 1,800 receptor sites/cell). Differentiation is initiated by attachment of the cells to the culture dish with poly-D-lysine and fibronectin and continued culture in serum-free medium. After 8 days in serum-free culture, differentiation is further induced with continuous Bt2cAMP treatment. Using this differentiation protocol, D2 receptor levels increase up to a maximum of 30 fmol/10(6) cells (18,000 receptors/cell) on day 20, the limit of culture viability. Cultures of 15-17 days (7-9 days of Bt2cAMP treatment) expressing receptor levels of 15-20 fmol/10(6) cells are used for pharmacological and functional characterization of D2 dopamine receptors. The pharmacology of competition for [3H]methylspiperone binding to differentiated Y-79 (dY-79) cell membranes by a series of dopaminergic antagonists verifies the D2 receptor nature of this site, exhibiting appropriate affinities and the following rank order of potency: YM-09151-2 approximately spiperone greater than domperidone approximately (+)-butaclamol approximately fluphenazine greater than chlorpromazine greater than (-)-sulpiride greater than (+)-sulpiride greater than promethazine greater than (+)-SCH 23390 much greater than (-)-butaclamol.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: National Institutes of Health, Bethesda, MD 20892.
authors.forename: F J
authors.initials: FJ
authors.lastname: Monsma
authors.forename: A C
authors.initials: AC
authors.lastname: Barton
authors.forename: D R
authors.initials: DR
authors.lastname: Sibley
mesh_terms: D000067956:Adenylyl Cyclase Inhibitors; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism; D005576:Colforsin / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology; D015259:Dopamine Agents / Q000378:metabolism; D018492:Dopamine Antagonists; D005134:Eye Neoplasms / Q000378:metabolism*; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D006801:Humans; D011954:Receptors, Dopamine / Q000378:metabolism* / Q000502:physiology; D017448:Receptors, Dopamine D2; D012175:Retinoblastoma / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D013134:Spiperone / Q000031:analogs & derivatives / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D000067956:Adenylyl Cyclase Inhibitors; D015259:Dopamine Agents; D018492:Dopamine Antagonists; D011954:Receptors, Dopamine; D017448:Receptors, Dopamine D2; D005576:Colforsin; D006165:Guanylyl Imidodiphosphate; D013134:Spiperone; C039167:3-N-methylspiperone; D004298:Dopamine