This Week in The Journal

Derivatives of the opium poppy have been used to ease pain and produce euphoria for millennia. Efforts to produce more potent agonists of endogenous opiate receptors continue. One of the strongest synthetic opiates is fentanyl. Paradoxically, fentanyl and other opiates prime nociceptors to generate exaggerated pain responses to future insults. See Araldi et al. for details. Photo by Kora27, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=59048260.