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Preparation and Delivery of Protein Microcrystals in Lipidic Cubic Phase for Serial Femtosecond Crystallography
Published on: September 20, 2016
Development and in vitro characterization of a novel bifunctional μ-agonist/δ-antagonist opioid tetrapeptide
Lauren C Purington1, Katarzyna Sobczyk-Kojiro, Irina D Pogozheva
1Medical School and College of Pharmacy, Department of Pharmacology, University of Michigan, Ann Arbor 48109, USA.
Abstract:
The development of tolerance to and dependence on opioid analgesics greatly reduces their long-term usefulness. Previous studies have demonstrated that co-administration of a micro-opioid receptor (MOR) agonist and δ-opioid receptor (DOR) antagonist can decrease MOR agonist-induced tolerance and dependence development after chronic exposure. Clinically, a single ligand displaying multiple efficacies (e.g., MOR agonism concurrently with DOR antagonism) would be of increased value over two drugs administered simultaneously. Guided by modeling of receptor-ligand complexes we have developed a series of potent non-selective opioid tetrapeptides that have differing efficacy at MOR and DOR. In particular, our lead peptide (KSK-103) binds with equal affinity to MOR and DOR but acts as a MOR agonist with similar efficacy but greater potency than morphine and a DOR antagonist in cellular assays measuring both G protein stimulation and adenylyl cyclase inhibition.
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