PAPupuncture has localized and long-lasting antinociceptive effects in mouse models of acute and chronic pain

Mol Pain. 2012 Apr 23:8:28. doi: 10.1186/1744-8069-8-28.

Abstract

Acupuncture has been used for millennia to treat pain, although its efficacy and duration of action is limited. Acupuncture also has brief (1-2 h) antinociceptive effects in mice and these effects are dependent on localized adenosine A₁ receptor (A₁R) activation. Intriguingly, adenosine 5'-monophosphate (AMP) is basally elevated near acupuncture points. This finding suggested that it might be possible to inhibit nociception for a longer period of time by injecting prostatic acid phosphatase (PAP, ACPP) into acupuncture points. PAP is an ectonucleotidase that dephosphorylates extracellular AMP to adenosine, has a long half-life in vivo and is endogenously found in muscle tissue surrounding acupuncture points. Here, we found that injection of PAP into the popliteal fossa--a space behind the knee that encompasses the Weizhong acupuncture point--had dose- and A₁R-dependent antinociceptive effects in mouse models of acute and chronic pain. These inhibitory effects lasted up to six days following a single injection, much longer than the hour-long inhibition provided by acupuncture. Antinociception could be transiently boosted with additional substrate (AMP) or transiently blocked with an A₁R antagonist or an inhibitor of phospholipase C. This novel therapeutic approach--which we term "PAPupuncture"--locally inhibits pain for an extended period of time (100x acupuncture), exploits a molecular mechanism that is common to acupuncture, yet does not require acupuncture needle stimulation.

Publication types

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

MeSH terms

  • Acid Phosphatase
  • Acupuncture Points
  • Acupuncture Therapy / methods*
  • Adenosine Monophosphate / metabolism
  • Animals
  • Chronic Pain / drug therapy*
  • Chronic Pain / therapy*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Pain Measurement
  • Protein Tyrosine Phosphatases / therapeutic use
  • Receptor, Adenosine A1 / metabolism

Substances

  • Receptor, Adenosine A1
  • Adenosine Monophosphate
  • Acid Phosphatase
  • prostatic acid phosphatase
  • Protein Tyrosine Phosphatases