Neurobiology Of Chronic Pain

Understanding the neurobiology of sensory synapses in the central nervous system provides us with basic knowledge of physiological and pathological pain, and has the potential to reveal possible drug targets for treating chronic pain. Pain-related synapses are found not only in the spinal cord dorsal horn, but also in many cortical areas. More importantly, recent evidence suggests that injury causing chronic pain also triggers long-term plastic changes in sensory synapses, including those in the spinal dorsal horn and frontal cortex. Changes in synaptic plasticity are not just limited in excitatory glutamatergic synapses but are also found in inhibitory synapses. This chapter reviews recent progress in these areas, in particular, integrative physiological investigations of chronic pain. Pain can be divided into two groups: physiological pain and pathological pain. This chapter also discusses peripheral nerves and dorsal root ganglion cells, plastic molecular targets for chronic pain, long-term potentiation in the anterior cingulate cortex, synaptic transmission at the spinal cord dorsal horn, and the role of cortical regions in pain perception.