Mitragynine (MG), the most prevalent bioactive alkaloid in kratom, displays nanomolar affinity for µ, κ and δ opioid receptors and produces opioid-dependent antinociception and dependence in rats. Here, using a battery of behavioral assays, we investigated MG effects in planarians. Acute MG exposure (< 100 μM) did not affect planarian motility or environmental preference, but reduced motility was detected during abstinence from chronic MG (1, 10 μM). MG (10 μM) produced place conditioning effects that were reduced by naltrexone (10 μΜ). These results suggest that MG produces opioid-sensitive reinforcing effects in planarians and MG pharmacology is conserved across different species.

Mitragynine (MG) 是 kratom 中最普遍的生物活性生物碱，对 µ、κ和 δ 阿片受体具有纳摩尔亲和力，并在大鼠中产生阿片依赖性镇痛和依赖性。在这里，使用一系列行为分析，我们研究了涡虫中的 MG 效应。急性 MG 暴露 (< 100 μM) 不影响涡虫运动或环境偏好，但在慢性 MG (1, 10 μM) 戒断期间检测到运动性降低。MG (10 μM) 产生的位置调节效应被纳曲酮 (10 μM) 降低。这些结果表明MG在涡虫中产生对阿片类药物敏感的增强作用，并且MG药理学在不同物种中是保守的。