Axonal hyperpolarization associated with acute hypokalemia: Multiple excitability measurements as indicators of the membrane potential of human axons

Satoshi Kuwabara, Kazuaki Kanai, Jia Ying Sung, Kazue Ogawara, Takamichi Hattori, David Burke, Hugh Bostock

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

Multiple nerve excitability measurements have been proposed for clinical testing of nerve function, and an important determinant of excitability is membrane potential. We report a patient with acquired hypokalemic paralysis in whom multiple excitability indices (stimulus -response curve, strength-duration properties, threshold electrotonus, recovery cycle) were measured during and after an acute hypokalemic attack (serum K+ level, 2.1 mEq/L and 4.5 mEq/L, respectively). During hypokalemia, there was a shift of the stimulus-response curve to the right, a decrease in strength-duration time constant, a "fanning-out" of responses during threshold electrotonus, a reduction in relative refractory period, and an increase in superexcitability; all of these indicate axonal hyperpolarization, presumably due to the K+ equilibrium potential being more negative. These indices returned to normal 20 h later, associated with normalization of the serum K+ level. These results demonstrate that the changes associated with hypokalemic paralysis are not confined to muscle and that axons undergo hyperpolarization in vivo. Multiple excitability measurements can be used as a tool to identify changes in membrane potential of human axons.

Original languageEnglish
Pages (from-to)283-287
Number of pages5
JournalMuscle and Nerve
Volume26
Issue number2
DOIs
Publication statusPublished - 2002
Externally publishedYes

Keywords

  • Hypokalemia
  • Membrane potential
  • Multiple excitability measurements
  • Refractory period
  • Superexcitability
  • Threshold of electrotonus

ASJC Scopus subject areas

  • Clinical Neurology
  • Neuroscience(all)

Fingerprint Dive into the research topics of 'Axonal hyperpolarization associated with acute hypokalemia: Multiple excitability measurements as indicators of the membrane potential of human axons'. Together they form a unique fingerprint.

  • Cite this