Cell-autonomous regulation of Mu-opioid receptor recycling by substance P

Cell Rep. 2015 Mar 24;10(11):1925-36. doi: 10.1016/j.celrep.2015.02.045.


How neurons coordinate and reprogram multiple neurotransmitter signals is an area of broad interest. Here, we show that substance P (SP), a neuropeptide associated with inflammatory pain, reprograms opioid receptor recycling and signaling. SP, through activation of the neurokinin 1 (NK1R) receptor, increases the post-endocytic recycling of the mu-opioid receptor (MOR) in trigeminal ganglion (TG) neurons in an agonist-selective manner. SP-mediated protein kinase C (PKC) activation is both required and sufficient for increasing recycling of exogenous and endogenous MOR in TG neurons. The target of this cross-regulation is MOR itself, given that mutation of either of two PKC phosphorylation sites on MOR abolishes the SP-induced increase in recycling and resensitization. Furthermore, SP enhances the resensitization of fentanyl-induced, but not morphine-induced, antinociception in mice. Our results define a physiological pathway that cross-regulates opioid receptor recycling via direct modification of MOR and suggest a mode of homeostatic interaction between the pain and analgesic systems.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Analgesics, Opioid / pharmacology
  • Animals
  • Cells, Cultured
  • Endocytosis
  • Fentanyl / pharmacology
  • HEK293 Cells
  • Humans
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Morphine / pharmacology
  • Neurons / drug effects
  • Neurons / metabolism*
  • Nociception
  • Protein Kinase C / metabolism
  • Protein Transport
  • Rats
  • Receptors, Neurokinin-1 / metabolism
  • Receptors, Opioid, mu / metabolism*
  • Substance P / pharmacology*
  • Trigeminal Ganglion / cytology


  • Analgesics, Opioid
  • Receptors, Neurokinin-1
  • Receptors, Opioid, mu
  • Substance P
  • Morphine
  • Protein Kinase C
  • Fentanyl