Influences of the Chemical Environment on Peripheral Afferent Neurons
Fine afferent fibers respond to a number of potentially harmful physiological stimuli including pressure, heat and a variety of noxious chemicals. Particularly striking is the repertoir of endogenous chemicals to which the afferent nerve terminal may be exposed and to which it is sensitive: as if it were specialized to “taste” its environment. The present discussion will focus, in the main, on pathophysiological chemical factors; as these have received most attention, particularly regarding the activation and sensitization of peripheral nociceptors following tissue injury and inflammation. In addition there are other cellular regulatory factors, often derived from target tissues, which are important for development and for maintaining the normal phenotype of afferent neurons. These substances may be present to a greater or lesser extent following tissue damage, inflammation or nerve injury and have a major influence in determining the long term properties of sensory neurons and other nearby cells. Important to all these chemical stimuli are the ways in which they interact at the nerve membrane to transduce and transmit their signals.
KeywordsNerve Growth Factor Dorsal Root Ganglion Dorsal Root Ganglion Neuron Afferent Nerve Terminal Inflammatory Hyperalgesia
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