Positive allosteric mechanisms of adenosine A1 receptor-mediated analgesia

Nature. 2021 Sep;597(7877):571-576. doi: 10.1038/s41586-021-03897-2. Epub 2021 Sep 8.


The adenosine A1 receptor (A1R) is a promising therapeutic target for non-opioid analgesic agents to treat neuropathic pain1,2. However, development of analgesic orthosteric A1R agonists has failed because of a lack of sufficient on-target selectivity as well as off-tissue adverse effects3. Here we show that [2-amino-4-(3,5-bis(trifluoromethyl)phenyl)thiophen-3-yl)(4-chlorophenyl)methanone] (MIPS521), a positive allosteric modulator of the A1R, exhibits analgesic efficacy in rats in vivo through modulation of the increased levels of endogenous adenosine that occur in the spinal cord of rats with neuropathic pain. We also report the structure of the A1R co-bound to adenosine, MIPS521 and a Gi2 heterotrimer, revealing an extrahelical lipid-detergent-facing allosteric binding pocket that involves transmembrane helixes 1, 6 and 7. Molecular dynamics simulations and ligand kinetic binding experiments support a mechanism whereby MIPS521 stabilizes the adenosine-receptor-G protein complex. This study provides proof of concept for structure-based allosteric drug design of non-opioid analgesic agents that are specific to disease contexts.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine / chemistry
  • Adenosine / metabolism
  • Allosteric Regulation / drug effects
  • Analgesia* / methods
  • Animals
  • Binding Sites
  • Disease Models, Animal
  • Female
  • GTP-Binding Protein alpha Subunit, Gi2 / chemistry
  • GTP-Binding Protein alpha Subunit, Gi2 / metabolism
  • Hyperalgesia / drug therapy
  • Lipids
  • Male
  • Neuralgia / drug therapy
  • Neuralgia / metabolism
  • Protein Stability / drug effects
  • Rats
  • Rats, Sprague-Dawley
  • Receptor, Adenosine A1 / chemistry
  • Receptor, Adenosine A1 / metabolism*
  • Signal Transduction / drug effects


  • Lipids
  • Receptor, Adenosine A1
  • GTP-Binding Protein alpha Subunit, Gi2
  • Adenosine