Reduced activity of adenylyl cyclase 1 attenuates morphine induced hyperalgesia and inflammatory pain in mice

Related Experiment Video

Updated: Aug 28, 2025

Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities
07:23

Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities

Published on: July 29, 2014

33.5K

Kayla Johnson1, Alexis Doucette1, Alexis Edwards1

  • 1Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN, United States.

Frontiers in Pharmacology
|September 19, 2022
PubMed

Insights

Reducing adenylyl cyclase 1 (AC1) activity or expression attenuates morphine tolerance and hypersensitivity. This approach also decreased inflammatory pain and improved nesting behaviors in mice.

Area of Science:

  • Neuroscience
  • Pharmacology
  • Pain Research

Background:

  • Opioid tolerance, opioid-induced hyperalgesia, and chronic pain are linked to increased adenylyl cyclase activity.
  • Adenylyl cyclase 1 (AC1) is implicated in these opioid-related pain states.

Purpose of the Study:

  • To investigate if reducing AC1 activity or expression can alleviate morphine tolerance, hyperalgesia, and inflammatory pain.
  • To test the therapeutic potential of targeting AC1 in pain management.

Main Methods:

  • Murine models were used to study opioid tolerance and hyperalgesia with static or escalating morphine treatment paradigms.
  • Systemic administration of an AC1 inhibitor (ST03437) and intrathecal delivery of a viral vector with short-hairpin RNA targeting Adcy1 were employed.
  • Inflammatory pain was induced using Complete Freund's Adjuvant (CFA), and behavioral tests assessed antinociception, motor performance, and nesting activities.

Main Results:

  • Systemic AC1 inhibition reduced morphine-induced hyperalgesia.
  • Intrathecal Adcy1 knockdown attenuated morphine-induced hypersensitivity without affecting acute antinociception or motor functions.
  • Adcy1 knockdown decreased inflammatory mechanical hyperalgesia and enhanced nesting behaviors post-CFA administration.

Conclusions:

  • Reducing AC1 activity or expression is a viable strategy to mitigate opioid-induced hyperalgesia and tolerance.
  • Targeting AC1 shows promise for managing inflammatory pain and improving well-being in pain models.
Keywords:
adenylyl cyclasehypersensitivityinflammationpaintolerance

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