GLYCINE - AN IMPORTANT POTENTIAL COMPONENT OF SPINAL SHOCK

Amino acid neurotransmitters (AANTs) play a major role in maintenance of muscle tone. Abnormal AANT concentrations are associated with hyper - or hypotonic states. Flaccidity from spinal shock commonly occurs af ter spinal cord injury (SCI) and may be associated with changes in AAN T concentrations. Ischemic SCIs created in the lumbar region of rabbit s by intraaortic balloon occlusion produced spastic or flaccid injurie s. Microdialysis sampling of AANTs from the injured segmental structur es was done 3 days after SCI. Evoked potentials were used to monitor s pinal cord stability. No significant changes in AANT levels occurred i n the spastic or flaccid group after 4 hour sampling. However, flaccid animals had baseline glycine levels 2-3 times higher (p < 0.001) than spastic animals or controls. High concentrations of the inhibitory AA NT glycine is associated with flaccidity following SCI, or spinal shoc k, but not spasticity. Glycinergic compounds directed toward suppressi on of excess muscle tone deserve further study