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Mu and delta opioid receptors diverge

Clifford J Woolf1

  • 1Neural Plasticity Research Group, Department of Anesthesia and Critical Care, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02129, USA. cwoolf@partners.org

Cell
|June 16, 2009
PubMed

Insights

Mu and delta opioid receptors target distinct pain pathways, challenging existing models. This suggests separate neuron populations mediate relief from different pain types, like heat versus mechanical stimuli.

Area of Science:

  • Neuroscience
  • Pain Research
  • Pharmacology

Background:

  • Current models propose mu and delta opioid receptors coexist on the same pain-sensing neurons.
  • This study investigates the cellular localization and functional roles of these receptors.

Discussion:

  • Evidence suggests mu and delta opioid receptors are expressed on distinct populations of pain-sensing neurons.
  • Agonists for mu and delta opioid receptors induce analgesia specific to either noxious heat or mechanical stimuli in mice.
  • This implies a functional segregation of receptor activity on different sensory fibers.

Key Insights:

  • Mu and delta opioid receptors do not share expression on the same nociceptive neurons.
  • Distinct receptor populations mediate analgesia for different sensory modalities (heat vs. mechanical).
  • This challenges the prevailing understanding of opioid receptor function in pain modulation.

Outlook:

  • Future research should explore the specific neuronal subtypes expressing mu and delta opioid receptors.
  • Understanding this segregation could lead to more targeted analgesic drug development.
  • This finding opens new avenues for investigating the neurobiology of pain and analgesia.

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