Related Experiment Video
Updated: May 20, 2026

Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities
Published on: July 29, 2014
Opioid receptor targeting ligands for pain management: a review and update
1Department of Solid Tumor Oncology, The Harry R. Horvitz Center for Palliative Medicine, Taussig Cancer Institute, 9500 Euclid Avenue R35, Cleveland, OH 44195, USA +1 216 444 7793 ; +1 216 636 3179 ; davism6@ccf.org.
Importance Of The Field:
Discovery and synthesis of analgesic ligands can potentially improve analgesia, reduce side effects, minimize psychologic dependence and delay analgesic tolerance.
Areas Covered In This Review:
This review covers opioid peptides and analogs and bifunctional opioid ligands, and bifunctional opioid/non-opioid ligands as new, potentially useful analgesics. Several lines of investigation have resulted in potentially useful agents.
What The Reader Will Gain:
Modifications of peptide structures have improved opioid receptor affinity, efficacy, stability, half-life and CNS penetrations. Opioid μ receptor agonists have been used to form multi-targeted directed ligands (MDL), which in animal models improve the therapeutic index of the analgesic relative to monovalent potent μ receptor agents. These new opioid ligands are reviewed in detail.
Take Home Message:
Modified opioid peptides and MDL ligands are potentially better analgesics than morphine.
Related Concept Videos
Analgesia and Pain Management
Opioid Receptors: Overview
Opioid Analgesics: Synthetic and Semisynthetic Opioids
Opioid Analgesics: Morphine and Other Natural Cogeners
Drug-Receptor Interaction: Agonist
Agonists can bind to receptors in different ways. Some agonists bind directly to the receptor's active site, mimicking the endogenous ligand's action.
Drug-Receptor Interactions
Several parameters, such as the drug's affinity for its receptor and its efficacy, which is its ability to activate the receptor, determine the drug's effect on the tissue.

