Neural changes in acute arthritis in monkeys. I. Parallel enhancement of responses of spinothalamic tract neurons to mechanical stimulation and excitatory amino acids

Brain Res Brain Res Rev. Jan-Apr 1992;17(1):1-13. doi: 10.1016/0165-0173(92)90002-4.


Somatosensory neurons of the spinal cord, including projection neurons, become hyperexcitable to mechanical stimuli during the development of experimental arthritis in rats and cats and hence are suggested to participate in the generation of arthritic hyperalgesia in humans. The experiments described here show a potentiation of the responses of spinothalamic tract (STT) neurons in monkeys during the development of an acute arthritis. The results demonstrate that the responses of STT neurons to mechanical stimuli and to iontophoretically applied excitatory amino acids (EAAs), particularly those acting at non-N-methyl-D-aspartate (non-NMDA) receptors, become enhanced during the development of inflammation produced by intra-articular injection of kaolin and carrageenan. Since the enhancement of both responses follows a similar time course, the results of this work suggest a role for EAAs in the hyperalgesia associated with arthritis and hence may provide a possible pharmacologic target for alleviation and/or prevention of arthritic pain.

Publication types

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

MeSH terms

  • Acute Disease
  • Afferent Pathways / drug effects
  • Afferent Pathways / physiology
  • Amino Acids / pharmacology*
  • Animals
  • Arthritis / chemically induced
  • Arthritis / physiopathology*
  • Biomechanical Phenomena
  • Electric Stimulation
  • Iontophoresis
  • Macaca fascicularis
  • Neural Pathways / drug effects
  • Neural Pathways / physiology
  • Spinal Cord / cytology
  • Spinal Cord / drug effects
  • Spinal Cord / physiopathology*
  • Thalamus / cytology
  • Thalamus / drug effects
  • Thalamus / physiopathology*


  • Amino Acids