Opioid Pharmacology under the Microscope

Detection of genome‐edited and endogenously expressed G protein‐coupled receptors

“…The ligand‐directed label described for the μ opioid receptor has been used to map opioid‐sensitive neurons in rat and mouse brains. Due to the function of the receptor being preserved after labelling, agonist‐mediated internalisation was visualised in locus coeruleus neurons [ 108 ] and understanding the expression pattern and responsiveness may aid the development of safer analgesics that target this receptor [ 112 ]. Ligand‐directed labelling of GPCRs offers a noninvasive approach to visualise receptors and opens up a huge number of possibilities to study ligand binding, receptor trafficking and signalling in endogenously and clinically relevant systems.…”

The Life Cycle of the Mu-Opioid Receptor

“…In light of these events, research on the biology of opioid receptors (ORs), the cellular mediators of opioid-induced effects, has gained significant momentum. Since their discovery in the second half of the 20 th century, many techniques have been used to study ORs; from radioligand binding in the 1970s and in situ hybridisation and molecular cloning in the 1990s [1], to the most recent visualisation of these receptors and their signalling in vitro and in vivo [2]. Of the four ORs subtypes [Mu (MOR), Delta (DOR), Kappa (KOR) and Opioid Receptor-Like 1 (ORL-1)], the MOR stands out for its role in opioid-induced analgesia and reward processing [3].…”

Editorial: 50 Years of Opioid Research and the International Narcotics Research Conference

“…Recent advances in optical imaging and biosensors are now providing new insights into the diversity of opioid signaling from a cell biological perspective. Jullié et al describe optical imaging approaches that have allowed us to address the importance of receptor dynamics in activating specific signaling pathways that could in turn dictate specific aspects of opioid physiology (Jullié et al, 2020). One such pathway could be the platelet-derived growth factor receptor beta signaling pathway, which Puig et al show contributes to the development of spinal opioid tolerance (Puig et al, 2020).…”