Enhancement of (-)-stepholidine on protein phosphorylation of adopamineand cAMP-regulated phosphoprotein in denervated striatum of oxidopaminelesioned rats

目的：研究左旋千金藤立定（ＳＰＤ）对羟多巴胺损毁大鼠纹状体中ＤＡＲＰＰ３２蛋白磷酸化程度的影响．方法：反磷酸化测定脱磷ＤＡＲＰＰ３２的含量．结果：ＳＰＤ不改变正常大鼠纹状体中ＤＡＲＰＰ３２磷酸化的程度，但能拮抗Ｄ１激动剂的作用；对羟多巴胺损毁大鼠的损侧纹状体，ＳＰＤ使脱磷ＤＡＲＰＰ３２的含量降低４４％，给予Ｄ１拮抗剂可以拮抗这一作用．结论：在损侧纹状体，ＳＰＤ显示Ｄ１激动剂的作用特性，增加ＤＡＲＰＰ３２蛋白的磷酸化，而在正常纹状体，ＳＰＤ表现为Ｄ１拮抗剂．

AIM: To study effects of (-)stepholidine (SPD) on the phosphorylation of a dopamine and cAMPregulated phosphoprotein (DARPP32) in the striatum of oxidopaminelesioned rats. METHODS: The amount of dephosphoDARPP32 was measured by a backphosphorylation assay. RESULTS: In the striatum of control rats, SPD per se had no effect on the phosphorylation of DARPP32, but it antagonized the decrease by 28 % of dephosphoDARPP32 induced by the D1 agonist SK&F38393. In the denervated striatum of oxidopaminelesioned rats, SPD decreased the amount of dephosphoDARPP32 by 44 % . The effect of SPD was completely counteracted by the concomitant administration of the D1 antagonist Sch23390. CONCLUSION: SPD exhibits D1 agonistic action on DARPP32 phosphorylation in the denervated striatum of oxidopaminelesioned rats, but it acts as a D1 antagonist in normal striatum.