Effects of Dietary n-3 Fatty Acids on the Phospholipid Molecular Species of Monkey Brain

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)