Anatomy and Physiology: Mechanisms of Nociceptive Transmission

Abstract

Nocicpetion is the measurable physiological response of specialized sensory receptors (nociceptors) to overt or potential tissue damage and is perceived in the CNS—via the spinothalamic tract, the thalamus, and finally different areas in the neocortex—as pain. Initially, noxious chemical, mechanical, or thermal stimuli are detected at nerve endings of primary sensory neurons with their soma located in the dorsal root ganglion (DRG) for body sensation, and in the trigeminal ganglion (gasserian ganglion) for face sensation. Specialized receptors () located at the cell membrane of sensory nerve endings translate the intensity of a given stimulus into action potential frequency, which results in the emission of glutamate and peptides in the respective area in the spinal cord dorsal horn (mostly superficial laminae I and II with some projections to lamina V).