title: The measurement of K+e concentration changes in human muscles during volitional contractions.
abstract: Changes of extracellular potassium concentration [( K+]e) were measured in human muscles during volitional isometric contractions using liquid ion-exchanger electrodes. In principle, an intramuscular injection needle containing a microelectrode with a side-pore was inserted into the brachioradialis muscle. After insertion of the needle, the glass ion-selective microelectrode (ISM) could be moved out of the protective trocar shield into the muscle tissue. The average values of [K+]e in human muscles during maximal effort rose from 4.5 mmol/l K+ to 9.5 mmol/l K+. These values correspond closely to those previously found in muscles of experimental animals.
mesh_terms: D005110:Extracellular Space / Q000032:analysis; D005542:Forearm; D006801:Humans; D008839:Microelectrodes; D009119:Muscle Contraction; D009132:Muscles / Q000032:analysis*; D011188:Potassium / Q000032:analysis*
chemical_list: D011188:Potassium