Transient receptor potential vanilloid 1 mediates pain in mice with severe sickle cell disease

Blood. 2011 Sep 22;118(12):3376-83. doi: 10.1182/blood-2010-12-327429. Epub 2011 Jun 27.

Abstract

Pain is the leading cause of emergency department visits, hospitalizations, and daily suffering in individuals with sickle cell disease (SCD). The pathologic mechanisms leading to the perception of pain during acute RBC sickling episodes and development of chronic pain remain poorly understood and ineffectively treated. We provide the first study that explores nociceptor sensitization mechanisms that contribute to pain behavior in mice with severe SCD. Sickle mice exhibit robust behavioral hypersensitivity to mechanical, cold, and heat stimuli. Mechanical hypersensitivity is further exacerbated when hypoxia is used to induce acute sickling. Behavioral mechanical hypersensitivity is mediated in part by enhanced excitability to mechanical stimuli at both primary afferent peripheral terminal and sensory membrane levels. In the present study, inhibition of the capsaicin receptor transient receptor potential vanilloid 1 (TRPV1) with the selective antagonist A-425619 reversed the mechanical sensitization at both primary afferent terminals and isolated somata, and markedly attenuated mechanical behavioral hypersensitivity. In contrast, inhibition of TRPA1 with HC-030031 had no effect on mechanical sensitivity. These results suggest that the TRPV1 receptor contributes to primary afferent mechanical sensitization and a substantial portion of behavioral mechanical hypersensitivity in SCD mice. Therefore, TRPV1-targeted compounds that lack thermoregulatory side effects may provide relief from pain in patients with SCD.

Publication types

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

MeSH terms

  • Action Potentials
  • Anemia, Sickle Cell / drug therapy
  • Anemia, Sickle Cell / metabolism*
  • Anemia, Sickle Cell / pathology
  • Animals
  • Capsaicin / adverse effects
  • Capsaicin / pharmacology
  • Disease Models, Animal
  • Female
  • Humans
  • Hyperalgesia / drug therapy
  • Hyperalgesia / metabolism*
  • Hyperalgesia / pathology
  • Hypoxia
  • Isoquinolines / pharmacology*
  • Male
  • Mice
  • Mice, Inbred Strains
  • Microelectrodes
  • Nociceptors / drug effects
  • Nociceptors / metabolism*
  • Pain / drug therapy
  • Pain / metabolism*
  • Pain / pathology
  • Pain Measurement / methods
  • Patch-Clamp Techniques
  • TRPV Cation Channels / antagonists & inhibitors*
  • TRPV Cation Channels / metabolism
  • Urea / analogs & derivatives*
  • Urea / pharmacology

Substances

  • 1-isoquinolin-5-yl-3-(4-trifluoromethyl-benzyl)-urea
  • Isoquinolines
  • TRPV Cation Channels
  • TRPV1 protein, mouse
  • Urea
  • Capsaicin