Abstracts Posters SICOT-SOF meeting Gothenburg 2010 _2_

Poster
Topic: Spine
Abstract number: 25473
CENTRAL NERVOUS SYSTEM EFFECTS OF NUCLEUS PULPOSUS EXPOSURE
Anna ERMUND 1 , Elin NILSSON 1 , Helena BRISBY 2 , Ingela HAMMAR 1
1 Neuroscience and Physiology, Göteborg (SWEDEN), 2 Clinical Sciences, Göteborg
(SWEDEN)
Changes in central nervous system neuronal responses may play an important role
in low back pain (LBP). Neuronal activity in the thalamus increases after acute
application of nucleus pulposus (NP) onto a dorsal root ganglion (DRG). We present
data on thalamic effects after NP leakage followed by compression of the DRG and
changes in synaptic plasticity in the ventral hippocampus (VH), a region involved in
pain perception. Rats and mice were subjected to experimental disc herniation. After
24 hours, neuronal responses in the thalamus evoked by electrical stimulation of
sciatic A fibres were recorded during DRG compression. Thirty minutes later NP was
reapplied onto the DRG. Neuronal responses in VH slices were investigated by
current pulses (50 ms interval, 20 s between pairs). The hippocampus was further
studied 3 and 7 days after NP application onto the DRG. Compression of the DRG
decreased the number of evoked responses in both NP and sham animals. A
repeated application of NP resulted in increased thalamic responses. In the VH 24
and 72 hours post surgery, the second pulse in a pair gave a larger response. In
naïve animals, both pulses gave responses of the same magnitude. Depression of
neuronal responses following mechanical dislocation may not contribute to increased
pain transmission but seems to counteract NP effects. Changes in the VH were
detected, indicating this area in low back pain modulation. These findings need
further investigation to identify signaling pathways involved in the establishment and
maintenance of LBP.
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