Glial activation: a driving force for pathological pain

Pain is classically viewed as being mediated solely by neurons, as are othe r sensory phenomena. The discovery that spinal cord glia (microglia and. as trocytes) amplify pain requires a change in this view. These glia express c haracteristics in common with immune cells in that they respond to viruses and bacteria, releasing proinflammatory cytokines,which create pathological pain. These spinal cord glia also become activated by certain sensory sign als arriving from the periphery. Similar to spinal infection,these signals cause release of proinflammatory cytokines,thus creating pathological pain. Taken together,these findings suggest a new, dramatically different approa ch to pain control, as all clinical therapies are focused exclusively on al tering neuronal, rather than glial,function.