370 Mechanism of agmatine prodrugs for alleviating chronic pain and opioid addiction

Objectives/Goals: There remains an urgent need for the development of safe and effective therapeutics for the long-term management of pain. We evaluated our novel analgesic in multiple pre-clinical models to assess its abuse liability, analgesic efficacy in models of chronic pain, and its mechanism of action in ex vivo spinal cord slices. Methods/Study Population: We evaluated SSA3’s abuse liability by utilizing an IV self-administration paradigm. In this experiment, rats are placed in a chamber and have the option to press a drug-infusion lever or a control lever. Abuse liability was determined based on extent of lever pressing on the drug-infusion lever. To evaluate chronic pain efficacy, mice underwent a spared nerve injury (SNI) which induces sustained hypersensitivity in their hind paw. Mice were then treated with SSA3, and their hypersensitivity was assessed. Finally, the mechanism of action was investigated through patch clamp electrophysiology recordings taken from excised spinal cord slices in mice. We recorded currents from neurons involved in the pain signaling pathway before and after application of our compound to observe drug efficacy at the cellular level. Results/Anticipated Results: Our results demonstrated that in a pre-clinical IV self-administration paradigm, SSA3 exhibited no abuse liability, indicated by a lack of drug intake or escalation of drug intake. Results from our SNI model of chronic pain reveal that when SSA3 is administered directly onto the spinal cord via intrathecal injection, it is efficacious in reversing the pain hypersensitivity established by the model, suggesting a spinally mediated mechanism of action. Finally, we observed that SSA3 effectively reduced the amplitude of NMDA receptor-mediated excitatory postsynaptic currents in a concentration-dependent manner. This reduction in amplitude suggests our compound’s analgesic efficacy comes from the inhibition of spinally mediated NMDA receptor signaling. Discussion/Significance of Impact: This investigation into the therapeutic potential of substituted agmatine for the management of chronic pain revealed several key insights. Our drug is efficacious in models of chronic pain and, importantly, lacks the abuse liability commonly seen with analgesic drugs. Our drug’s mechanism of action involves inhibition of spinal NMDA receptors.