Temporal changes of astrocyte activation and glutamate transporter-1 expression in the spinal cord after spinal nerve ligation-induced neuropathic pain

Anat Rec (Hoboken). 2008 May;291(5):513-8. doi: 10.1002/ar.20673.

Abstract

Astrocyte activation is involved in the neuropathic pain. As a glutamate scavenger, the glutamate transporter-1 (GLT-1) is exclusively expressed on the astrocytes and probably correlates with astrocyte activation. In the present study, we attempted to clarify the temporal changing courses of astrocyte activation and GLT-1 expression, as well as their correlations induced by a neuropathic pain model, namely, spinal nerve ligation (SNL) in which rapidly appearing (<3 days) and persistent (>21 days) mechanical allodynia and thermal hyperalgesia were presented. Immunofluorescent staining showed that GLT-1 was expressed exclusively in most (not all) of the astrocytes, even when the GLT-1 expression reached its peak. The expression of GLT-1 displayed an interesting biphasic change, with an initial up-regulation followed by a down-regulation after SNL. Our results also demonstrated that SNL induced a marked and long-term (>21 days) activation of astrocytes in the ipsilateral spinal dorsal horn. These results suggest that astrocyte activation, the change of GLT-1 expression and the potential relationship between them might play key roles in the induction and/or maintenance of neuropathic pain. The present results provide novel clues in understanding the mechanisms underlying the involvement of astrocytes and GLT-1 in the neuropathic pain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Astrocytes / metabolism*
  • Behavior, Animal / physiology*
  • Excitatory Amino Acid Transporter 2 / metabolism*
  • Ligation
  • Male
  • Neuralgia / metabolism*
  • Neuralgia / physiopathology
  • Rats
  • Rats, Sprague-Dawley
  • Spinal Cord / metabolism*
  • Time Factors

Substances

  • Excitatory Amino Acid Transporter 2