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Subcontracture depolarization alters doublet potentiation
Author(s) -
Barnes William Stephen
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.600.4
Subject(s) - depolarization , long term potentiation , chemistry , stimulation , pulse (music) , electrophysiology , nuclear magnetic resonance , analytical chemistry (journal) , biophysics , physics , medicine , voltage , chromatography , biology , biochemistry , receptor , quantum mechanics
Doublet potentiation occurs when a brief, high‐frequency burst of pulses is added to a subtetanic train of pulses. The purpose of this investigation was to determine the effect of subcontracture K + ‐induced depolarization on doublet potentiation. Sartorii muscles (60‐70 mg) from R. pipiens were excised and mounted in water‐jacketed (20°C) chambers containing oxygenated (100%) Ringer's solution (R; pH 7.2) containing 2.5 mM KCl (R+KCl 2.5 ). Muscles were exposed to an 800 ms train (20 Hz) of supramaximal square‐wave pulses (.2 ms) via field stimulation. An additional pulse was inserted between the 9 th and 10 th pulses (ISI = 10 ms). Peak tensions (PT, g) for contractions (PT A‐E ) between the eighth and twelveth pulses were determined. Tension‐time integrals (TTI, g·s) were calculated. This protocol was then repeated with the [KCl] of R increased incrementally up to 15 mM/L. Subcontracture depolarization lessens the effect of transient high‐frequency paired stimulation and may mitigate its potential as a motor control strategy.