The most commonly used analgesics are cyclooxygenase inhibitors (NSAIDs) and mu-opioid receptor agonists (e.g., morphine), which are limited by severe side effects such as stomach bleeding or ulcers, hypertension, kidney problems, constipation, respiratory failure, and addiction. To overcome these problems, selective kappa-opioid receptor agonists (e.g., U50,488H) have been developed. However, they were found to produce sedation, depressive-like behaviors and hallucinations, which result from kappa-receptor activation in the brain. In this collaborative, interdisciplinary project involving pain researches, biochemists and veterinarians, we develop and investigate nanocarriers (González-Rodríguez et al., eLife 2017) to deliver kappa-opioids selectively to peripheral inflamed tissue to inhibit pain at the site of its origin, without adverse effects produced by classical opioids, in rodent models and in veterinary practice.   
Group members involved: Halina Machelska, Christoph Stein, Dominika Labuz, Roger Negrete