Nematode Caenorhabditis elegans (C. elegans) exhibited a vigorous swimming behavior in liquid medium. Addition of dopamine inhibited the swimming behavior, causing paralysis in 65% of wild-type nematodes. Interestingly, phytocannabinoids cannabidiol (CBD) or cannabidivarin (CBDV), caused paralysis in 40% of the animals. Knockout of DOP-3, the dopamine D2-like receptor critical for locomotor behavior, eliminated the paralysis induced by dopamine, CBD, and CBDV. In contrast, both CBD and CBDV caused paralysis in animals lacking CAT-2, an enzyme necessary for dopamine synthesis. Co-administration of dopamine with either CBD or CBDV caused paralysis similar to that of either phytocannabinoid treatment alone. These data support the notion that CBD and CBDV act as functional partial agonists on dopamine D2-like receptors in vivo. The discovery that dopamine receptor is involved in the actions of phytocannabinoids moves a significant step toward our understanding of the mechanisms for medical uses of cannabis in the treatment of neurological and psychiatric disorders.

线虫秀丽隐杆线虫( C. elegans)在液体介质中表现出强烈的游泳行为。添加多巴胺会抑制游泳行为，导致 65% 的野生型线虫瘫痪。有趣的是，植物大麻素大麻二酚 (CBD) 或大麻二酚 (CBDV) 导致 40% 的动物瘫痪。敲除 DOP-3，一种对运动行为至关重要的多巴胺 D2 样受体，消除了由多巴胺、CBD 和 CBDV 引起的麻痹。相比之下，CBD 和 CBDV 都会导致缺乏 CAT-2（多巴胺合成所必需的酶）的动物瘫痪。多巴胺与 CBD 或 CBDV 的共同给药引起的麻痹类似于单独使用植物大麻素治疗的麻痹。这些数据支持 CBD 和 CBDV 作为体内多巴胺 D2 样受体的功能性部分激动剂的观点。多巴胺受体与植物大麻素的作用有关的发现向我们了解大麻在治疗神经和精神疾病中的医疗用途机制迈出了重要的一步。