Up-regulation of D1 dopamine receptors in SK-N-MC cells after chronic treatment with SCH 23390

Regulation of the D1 dopamine receptor due to chronic treatment with an antagonist SCH 23390 was studied in SK-N-MC cells. Prolonged treatment (72 h) with the antagonist resulted in a 70% increase in density of D1 dopamine receptors in SK-N-MC cells. This up-regulation of D1 dopamine receptor was time and concentration dependent. The optimum time and concentration were 72 h and 10 μM, respectively. Another antagonist, (+) Butaclamol also upregulated the D1 dopamine receptor, although the effect was less than SCH 23390. This up-regulation of the D1 dopamine receptor involved the synthesis of new receptor molecules, because the treatment of the cells with cycloheximide resulted in a significant decrease in upregulation after prolonged treatment with an antagonist. These results indicate that up-regulation of the D1 dopamine receptor after chronic treatment with an antagonist can also occur in cell culture which provides a good working model to study various type of regulations at the biochemical and molecular levels.