ItchingWIKIMEDIA COMMONS, MUHAMMAD MAHDI KARIM
To explain why some patients get an itch along with their pain relief when given morphine, researchers examined two variants of the morphine receptor and found they relay two signals—one that relieves pain and one that induces an itching sensation. The finding of distinct cellular pathways suggests a way to uncouple these effects.
X.Y. Liu et al., "Unidirectional Cross-Activation of GRPR by MOR1D Uncouples Itch and Analgesia Induced by Opioids," Cell, 147:447-58, 2011. Free F1000 Evaluation
Hormones that relay hunger or satiety trigger a feedback loop in the brain that continues long after the hormones are degraded, creating a memory of hunger that may influence the success of dieters.
Y. Yang, et al., "Hunger states switch ...
