Relevance between striatal expression of Fos, proenkephalin mRNA, prodynorphin mRNA and rotation induced by l-stepholidine in 6-hydroxydopamine-lesioned rats.

AIM

To study that l-stepholidine (SPD) regulates the expression of proenkephalin (PENK) and prodynorphin (PDYN) mRNA and Fos in the striatum after rotational test in the 6-hydroxydopamine (6-OHDA)-lesioned rats.

METHODS

PENK and PDYN mRNA levels were examined with in situ hybridization, and Fos expression was detected with immunocytochemistry. The data were semi-quantified with image analyzer.

RESULTS

(1) Following repeated SPD treatment, the rotation was kept on high activity in the 6-OHDA-lesioned rats. (2) SPD significantly elicited Fos expression in both sides of striatum, particularly in the denervated one. Repeated administration of SPD, Fos expression declined on both sides, particularly in the intact one. (3) In the denervated striatum of 6-OHDA-lesioned rats, the PENK mRNA level was extremely increased vs that in the intact striatum. This high level of PENK mRNA was significantly reduced by 7-d treatments of SPD. SPD also reduced the level of PENK mRNA in the intact striatum. However, the level of PDYN mRNA did not show significant change in both sides of striatum after denervation or SPD treatment.

CONCLUSION

In the 6-OHDA-lesioned rats, the rotation induced by SPD was kept on a high activity, which was in pace with the inducement of Fos expression and the reduction of expression of PENK mRNA in the denervated striatum. But then the lesion and SPD treatment had no remarkable effect on the expression of PDYN mRNA.