A new study has produced evidence of the source of chronic pain in humans, revealing several new targets for pain treatment. The paper examined human dorsal root ganglia, specialized nerve cells clustered near the base of the spine removed from cancer patients undergoing surgery.
The paper — published March 19 in Brain, one of the world’s oldest neurology journals — examined specialized nerve cells clustered near the base of the spine. Researchers took advantage of an exceedingly rare opportunity to study these nerves, called dorsal root ganglia (DRG), removed from cancer patients undergoing surgery at MD Anderson.
The researchers cataloged variations in RNA expression in the dorsal root ganglia cells of patients differing by pain state and sex. Using RNA sequencing, a specialized form of gene sequencing, on those DRG cells yielded a list of promising biochemical pathways for which researchers might be able to devise analgesic drugs.
«This surgery is not done at many places,» said Dr. Ted Price, a senior author of the paper and Eugene McDermott Professor of neuroscience in UT Dallas’ School of Behavioral and Brain Sciences. «Our patient cohort of 21, though it doesn’t sound like many, is huge relative to any prior human chronic pain study using RNA sequencing.»
Chronic pain is labeled as neuropathic when it is caused by damage to nerve cells. Examples include phantom limb syndrome, pain resulting from a stroke and the «pins and needles» sensations associated with diabetes.
«Peripheral nerve cells usually fire because of some external stimulus — you get burned, or your fingers are pinched, et cetera,» said UT Dallas research scientist Pradipta Ray, one of the study’s three lead authors. «Sometimes, the neurons just keep firing with no current stimulus, leaving people in constant pain.»
«If these cells are firing without any stimulus we can detect, we call that spontaneous activity,» Price said. «And we’ve taken a significant step in this study by locating biophysical conduits by which that painful activity travels in the human body.»
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