Amino Acids in Spinal Dorsal Horn of Patients During Surgery for Neuropathic Pain or Spasticity

Neuroreport. 2000 Jun 5;11(8):1795-8. doi: 10.1097/00001756-200006050-00040.


A specific microdialysis probe combined with high performance liquid chromatography analysis was used to compare the basal levels of extracellular amino acids (AAs) in the dorsal horn (DH) between two groups of patients undergoing spinal surgery for the treatment of peripheral neuropathic pain (n = 5) or disabling spasticity (n = 5). A stabilized concentration was reached in the dialysates 45 min after probe implantation for excitatory AAs (glutamate and aspartate) and inhibitory AAs (GABA and glycine). A significant increase in the ratios aspartate/GABA and aspartate/glycine was found in the group of patients suffering from neuropathic pain. This study shows the feasibility of a microdialysis investigation in the DH of patients during a neurosurgical operation and supports in humans the hypothesis of an imbalance between excitatory AAs and inhibitory AAs within the DH in neuropathic pain states, as suggested by previous animal studies.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / metabolism*
  • Aspartic Acid / metabolism
  • Chromatography, High Pressure Liquid
  • Extracellular Space / metabolism
  • Feasibility Studies
  • Glutamic Acid / metabolism
  • Glycine / metabolism
  • Humans
  • Intraoperative Period
  • Microdialysis
  • Muscle Spasticity / metabolism*
  • Neuralgia / surgery*
  • Peripheral Nervous System Diseases / surgery*
  • Spinal Cord / metabolism*
  • gamma-Aminobutyric Acid / metabolism


  • Amino Acids
  • Aspartic Acid
  • Glutamic Acid
  • gamma-Aminobutyric Acid
  • Glycine