Effects of L-dopa on cells expressing D_2 receptors and level of dopamine transmitter in hemiparkinsonian rats

OBJECTIVE To investigate the effects of L-dopa on cells expressing D2 receptors and level of dopamine transmitter in striatum in the treatment of Parkinson's disease (PD) . METHODS Hemiparkinsonian model was established on rats pretreated with 6-hydroxy-dopamine. The cells of expression of D2 receptor and the level of dopamine transmitters in striatum were detected respectively by immunohisto-chemical staining and HPLC before and after introducing L-dopa (100 mg·kg-1·d-1,ip) to PD model for 15 d.RESULTS Compared with before-treatment group, decreased significantly whereas the level of dopamine transmitter at the lesioned side striatum increased significantly after L-dopa intervention to PD model, the cells expressing D2 receptor at the lesioned side striatum( P 0.01) . CONCLUSION The cells expressing of D2 receptor are compensatively upregulated at the lesioned side striatum in hemiparkinsonian rats. However, this upregulative effect can be reversed by L-dopa intervention to a great extent.