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The effects of KATP channels on skeletal muscle fatigue and recovery are dependent on muscle stimulus frequency and fibre type (1102.9)
Author(s) -
Charter Mackenzie,
Murrant Coral
Publication year - 2014
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.28.1_supplement.1102.9
Subject(s) - glibenclamide , stimulus (psychology) , pinacidil , contraction (grammar) , muscle fatigue , chemistry , medicine , skeletal muscle , endocrinology , biophysics , cardiology , electromyography , biology , physical medicine and rehabilitation , psychology , psychotherapist , diabetes mellitus
ATP sensitive potassium (KATP) channels are hypothesized to protect against ATP depletion during maximal muscle contraction by decreasing force production, however their function in submaximal contractions and recovery is unknown. We sought to test whether KATP channels altered the force of contraction during fatigue and recovery of mouse slow (soleus; SOL) and fast (extensor digitorum longus; EDL) twitch muscle, in vitro, at maximal and submaximal stimulus frequencies. We fatigued SOL (60Hz, 60 contractions per minute (CPM) and 20Hz, 60CPM) and EDL (100Hz, 60CPM and 40Hz, 60CPM) for 5 minutes in the absence or presence of a KATP channel inhibitor (10‐5M glibenclamide; GLIB) or a KATP channel opener (10‐5M pinacidil; PIN) and then observed recovery (SOL: 60Hz 0.6 CPM and 20Hz, 0.6CPM; EDL:100Hz 0.6CPM and 40Hz 0.6 CPM). GLIB had no effect on fatigue or recovery of SOL or EDL at maximum stimulus frequencies but significantly attenuated force in SOL (12.2%) and EDL (6.9%) at submaximal frequencies. GLIB significantly enhanced force during recovery of SOL by 22.5% at submaximal stimulus frequencies. PIN did not affect fatigue of SOL or EDL at maximal stimulus frequencies or the recovery of SOL but significantly attenuated force of EDL during recovery by 8.9%. PIN had no effect on fatigue or recovery during submaximal contractions. Thus, the effect of KATP channels is dependent on both fibre type and stimulus frequency. Grant Funding Source : Supported by NSERC, Canada