Carnivorous marine molluscs of the Conus genus possess potent venoms which induce rapid paralysis of predators and prey. The bioactive components comprise an enormous array of peptide molecules, termed conotoxins, which exhibit high affinity and specificity for important neurophysiological receptors and ion channels. Conotoxins possess multiple disulfide bonds providing structural and biological stability and have thus been adopted as biomedical research tools and therapeutic leads, namely as analgesics for chronic pain, which is poorly managed clinically. Vc1.1 is a 16 amino acid peptide belonging to the α-conotoxin subfamily, which are potent nAChR antagonists with a native CysI-III, CysII-IV disulfide connectivity. Recently, several members of this family have been shown to also inhibit VGCCs via a novel mechanism involving the GABAB receptor. These pharmacological targets are thought to underlie the analgesic effects of Vc1.1 when administered in various rodent models of chronic neuropathic pain. We have shown that a truncated, single-disulfide loop 1 analogue, [Ser3]Vc1.1(1-8), is sufficient for both VGCC inhibition and in vivo analgesia in a rodent model of chronic visceral pain, providing a new lead molecule for pre-clinical development. However, the key structural and pharmacological determinants of [Ser3]Vc1.1(1-8) that mediate its receptor interactions and therapeutic effects are still poorly understood. In order to elucidate structure-activity relationships, we have chemically synthesised a library of positional mutants, including Ala, Asp, Lys, and D-amino acid scans, and have also engineered disulfide-bond mimetics to improve in vivo stability and therapeutic potential. Using NMR spectroscopy and electrophysiological assays to compare structural and pharmacological characteristics of [Ser3]Vc1.1(1-8) analogues, combined with in vivo neuropathic pain assays, we aim to develop a potent and stable analgesic for treatment of chronic pain.