Ropinirole,a dopamine agonist,has similar effect of dopamine but without ergoline structure by which its stronger binding power with dopamine D2 receptor may be explained.

匹尼种类似多巴胺的多巴胺激动剂，第代多巴胺激动剂不同的有角林结构。匹尼的非角林结构可以说明其多巴胺D2受体有较高的结合力。