Scientists Design Cannabis-Based Painkillers That Avoid Typical Side Effects

Cannabis-based medicines have long promised effective pain relief, but their development has been hampered by significant side effects that limit clinical use. Now, researchers at Zhejiang University have engineered a potential solution by designing CB1 receptor agonists that selectively activate beneficial pathways while avoiding problematic ones.

The team used structure-activity relationship analyses to rationally design two compounds, LZD503 and LZD505, that preferentially activate Gi signaling pathways in CB1 receptors. Their design strategy involved precise structural modifications to disrupt specific molecular interactions and minimize conflicts within the receptor's binding pocket, promoting selective pathway activation.

Cryo-electron microscopy confirmed that these engineered compounds bind to CB1 receptors in conformations that favor Gi-biased signaling. In mouse studies, both compounds demonstrated effective pain relief while avoiding the unwanted responses typically associated with CB1 activation, such as cognitive impairment and motor dysfunction.

This breakthrough could lead to a new generation of cannabis-based analgesics that provide therapeutic benefits without limiting side effects. The structural insights gained from this work establish a framework for developing additional CB1-targeted drugs with improved safety profiles, potentially offering alternatives to opioid painkillers in clinical practice.