Objective      To investigate the expression of dopamine D

1

-like receptors in mouse macrophages RAW264.7 and the role of the receptors in ox-LDL-induced proli

feration of macrophages.       Methods      Mouse macrophages RAW264.7 were used as target cells. Western blotting was used to detect the expression of dopamine D

1

-like receptors in RAW264.7 cells. The RAW264.7 cells were treated by ox-LDL (10

20 and 40 μg/mL) with or without the presence of fenoldopam (the receptor agonist

10

-7

mol/L)

SCH23390 (antagonist

10

-6

mol/L) and PD98059 (special inhibitor of MAPK signal pathway

10

-6

mol/L). The proliferation of RAW264.7 cells was determined by

3

H- TdR incorporation

and Western blotting was employed to measure the expression of p-ERK

total ERK1/2

and proliferation cell nuclear antigen (PCNA).       Results      RAW264.7 cell expressed D

1

-like receptors in mouse macrophages RAW264.7. Fenoldopam (10

-7

mol/L) and PD98059 (10

-6

mol/L) significantly inhibited the ox-LDL-induced proliferation of RAW264.7 cells

and SCH23390 (10

-6

mol/L)reversed the inhibited the proliferation of RAW264.7 cells pretreated by fenoldpam (10

-7

mol/L). In addition

in presence of PD98059

fenoldopam had no effect in this process. Fenoldpam decreased the expression of PCNA and p-ERK which were formerly enhanced by ox-LDL.       Conclusion      D

1

-like receptors are expressed in mouse macrophages

and activation of the receptors reduces ox-LDL-induced proliferation of the cells

which may be through MAPK/ERK signal pathway.