Expression of dopamine D1 receptor in Sf9 insect cells and agonism of l-12-chloroscoulerine on recombinant D1 receptor.

AIM: To express dopamine D1 receptor in baculovirus-Sf9 cell system, and to investigate the effects of l-12-chloroscoulerine (l-CSL) on the recombinant D1 receptor (D1R). METHODS: The recombinant baculovirus, Autographa californica nuclear polyhedrosis virus bearing D1R (AcNPV- D1R) was generated, and then was used to produce recombinant D1R in Sf9 insect cells. Expression of D1R in Sf9 cells was monitored by [3H]SCH23390 binding assay. The effects of l-CSL on recombinant D1R were investigated by [3H]SCH23390 binding assay and cAMP assay. RESULTS: The recombinant baculovirus AcNPV bearing D1R cDNA was generated, and was successfully expressed in Sf9 insect cells. The expression level of (Bmax) was (0.94+/-0.06) nmol/g protein. The Kd value of [3H]SCH23390 was (1.9+/-0.3) nmol/L, which was consistent with the previous results from calf striatum tissues. l-CSL had a high affinity to recombinant D1R with Ki value of (6.3+/-1.4) nmol/L, and increased the intracellular cAMP level in a concentration-dependent manner with EC50 value of 0.72 micromol/L and 95 % confidence limit was 0.67-0.77 micromol/L. Thus l-CSL has the D1 receptor agonism. CONCLUSION: An efficient baculovirus-Sf9 insect cell system for dopamine D1 receptor was constructed and l-CSL presented the D1 receptor agonism on cellular-molecular level directly.