Cell Signaling

Opioid Receptors Up to Scratch

See allHide authors and affiliations

Science  18 Nov 2011:
Vol. 334, Issue 6058, pp. 878
DOI: 10.1126/science.334.6058.878-b

Itching and pain are two distinct sensations, and it's probably not advantageous to mix the two, given that they cause very different responses—scratching in response to the former and withdrawal in response to a painful stimulus. Nevertheless, there seems to be some overlap of the two sensations. For example, a common side effect of injection of opioids into the spinal cord for pain management is opioid-induced itch. Liu et al. report that this effect of the opioid morphine is brought about by heterodimeric receptors composed of the µ-opioid receptor (MOR1D), which binds morphine, and the gastrin-releasing peptide receptor (GRPR), which binds GRP. This hybrid receptor only allows signaling of itch sensation as binding of morphine activates GRPR, but binding of GRP doesn't activate MOR1D. Specifically targeting this heterodimeric receptor holds promise as a strategy to prevent opioid-induced itch while retaining the analgesic effects of opioids.

Cell 147, 447 (2011).

Navigate This Article