Spinal cord stimulation attenuates augmented dorsal horn release of excitatory amino acids in mononeuropathy via a GABAergic mechanism.
Neuropathic pain may be effectively relieved by electric stimulation of the spinal cord (SCS). However, the underlying mechanisms for the ensuing pain relief are poorly understood. In a rat model of neuropathy displaying hypersensitivity to innocuous tactile stimuli, (allodynia), we have earlier demonstrated that SCS may normalise withdrawal response thresholds. In the present study, using microdialysis, it is shown that SCS induces a decreased release of the dorsal horn excitatory amino acids (EAA), glutamate and aspartate, concomitant with an increase of the GABA release. Local perfusion with a GABA(B)-receptor antagonist in the dorsal horn transiently abolishes the SCS-induced suppression of the EAA release. Thus, the effect of SCS on neuropathic pain and allodynia may be due to an activation of local GABAergic mechanisms inhibiting the EAA release which is chronically elevated in such conditions.
Cui
J G
JG
Department of Neurosurgery, Karolinska Institute Centre for Pain Research, Stockholm, Sweden.
O'Connor
W T
WT
Ungerstedt
U
U
Linderoth
B
B
Meyerson
B A
BA
D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D004558:Electric Stimulation; D018846:Excitatory Amino Acids / Q000378:metabolism*; D018682:GABA Agents / Q000494:pharmacology; D058785:GABA-A Receptor Agonists; D058787:GABA-A Receptor Antagonists; D058786:GABA-B Receptor Agonists; D058788:GABA-B Receptor Antagonists; D018698:Glutamic Acid / Q000378:metabolism; D008297:Male; D017551:Microdialysis; D010523:Peripheral Nervous System Diseases / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000378:metabolism; D018080:Receptors, GABA-B / Q000378:metabolism; D012584:Sciatic Nerve / Q000502:physiology; D013116:Spinal Cord / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D018846:Excitatory Amino Acids; D018682:GABA Agents; D058785:GABA-A Receptor Agonists; D058787:GABA-A Receptor Antagonists; D058786:GABA-B Receptor Agonists; D058788:GABA-B Receptor Antagonists; D011963:Receptors, GABA-A; D018080:Receptors, GABA-B; D001224:Aspartic Acid; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid