Applied physiology: neuropathic pain

Abstract

This chapter focuses on peripheral and spinal mechanisms of neuropathic pain. Inflammatory mediators can produce excitation of neurons in the peripheral nervous system and central nervous system. Nerve injury can lead to cell death and anatomical reorganization. A loss of inhibitory mechanisms and increase in excitatory mechanisms are associated with increased activity in the spinal cord in neuropathic pain. Microglia is activated in neuropathic pain and release pronociceptive substances which can activate neurons in the spinal cord. Unravelling the mechanisms involved in neuropathic pain requires the use of laboratory animal models that replicate as far as possible the different pathophysiological changes present in patients. The sensory input from primary sensory neurons is transferred, via their central axons, to second-order neurons in the dorsal horn of the spinal cord. In addition to the peripheral and spinal mechanisms discussed, supraspinal mechanisms are thought to play an important role in neuropathic pain.