The dynamic sodium current of human skeletal muscle.
The dynamic sodium current (INa) was investigated in intact external intercostal muscle bundles dissected from 5 volunteers. Only fibres with a resting membrane potential negative to -80 mV were used. Stepwise changes were imposed on the membrane potential using the "loose-patch" clamp technique. The following results concerning INa are means +/- SD obtained from 27 fibres: threshold at -42.7 +/- 5.2 mV; maximal amplitude of 9.7 +/- 7.8 mA/cm2 at -1 +/- 13 mV. Inactivation: starting from the resting potential, maximally 90% of INa max could be activated; 50% of INa max were inactivated at Eh = -66.2 +/- 5.8 mV; the slope of the inactivation (h infinity -) curve at this potential was kh = 7.1 +/- 1.6 mV.
Zite-Ferenczy
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Matthias
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Rüdel
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D000200:Action Potentials; D004553:Electric Conductivity; D005260:Female; D006801:Humans; D007473:Ion Channels / Q000502:physiology; D008297:Male; D009132:Muscles / Q000502:physiology*; D012508:Sarcolemma / Q000502:physiology; D012964:Sodium / Q000502:physiology*
D007473:Ion Channels; D012964:Sodium