Premium
Microneurography, impulse conduction, and paresthesias
Author(s) -
Burke David
Publication year - 1993
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880161005
Subject(s) - microneurography , depolarization , neuroscience , hyperpolarization (physics) , hyperventilation , medicine , nerve conduction velocity , membrane potential , ischemia , chemistry , anesthesia , cardiology , psychology , baroreflex , heart rate , organic chemistry , nuclear magnetic resonance spectroscopy , blood pressure
It is possible to learn more about peripheral nerve function in human subjects than is obtainable with routine nerve conduction studies, and thereby to study the basis of “positive” symptoms, such as paresthesias. Using microneurography, ectopic impulse activity in cutaneous afferents has been recorded in patients suffering from neurologic disorders and in normal subjects in whom paresthesias were provoked by hyperventilation, prolonged tetanization of cutaneous nerves and ischemia. Using relatively simple modifications of standard nerve conduction techniques, the increases in axonal excitability responsible for this ectopic activity have been documented in human volunteers. Hyperventilation increases axonal excitability butdoes not change supernormality, probably because Na + channels are activated by the decrease in [Ca 2+ ] on the axonal membrane. Prolonged tetanic stimulation and ischemia probably share similar mechanisms. At least in motor axons, postischemic ectopic activity occurs when the hyperpolarization that results from activation of the Na + /K + pump lowers the membrane potential below the equilibrium potential for K + . A high extracellular [K + ] can then result in an inward current producing depolarization and possibly triggering regenerative processes. © 1993 John Wiley & Sons, Inc.