Myosin heavy chain isoform composition and Ca2+ transients in fibres from enzymatically dissociated murine soleus and extensor digitorum longus muscles
- 4 January 2010
- journal article
- Published by Wiley in The Journal of Physiology
- Vol. 588 (1), 267-279
- https://doi.org/10.1113/jphysiol.2009.180893
Abstract
Electrically elicited Ca(2+) transients reported with the fast Ca(2+) dye MagFluo-4 AM and myosin heavy chain (MHC) electrophoretic patterns were obtained in intact, enzymatically dissociated fibres from adult mice extensor digitorum longus (EDL) and soleus muscles. Thirty nine fibres (23 from soleus and 16 from EDL) were analysed by both fluorescence microscopy and electrophoresis. These fibres were grouped as follows: group 1 included 13 type I and 4 type IC fibres; group 2 included 2 type IIC, 3 IIA and 1 I/IIA/IIX fibres; group 3 included 4 type IIX and 1 type IIX/IIB fibres; group 4 included 2 type IIB/IIX and 9 type IIB fibres. Ca(2+) transients obtained in groups 1, 2, 3 and 4 had the following kinetic parameters (mean +/- s.e.m.): amplitude (F/F): 0.61 +/- 0.05, 0.53 +/- 0.08, 0.61 +/- 0.06 and 0.61 +/- 0.03; rise time (ms): 1.64 +/- 0.05, 1.35 +/- 0.05, 1.18 +/- 0.06 and 1.14 +/- 0.04; half-amplitude width (ms): 19.12 +/- 1.85, 11.86 +/- 3.03, 4.62 +/- 0.31 and 4.23 +/- 0.37; and time constants of decay (tau(1) and tau(2), ms): 3.33 +/- 0.13 and 52.48 +/- 3.93, 2.69 +/- 0.22 and 41.06 +/- 9.13, 1.74 +/- 0.06 and 12.88 +/- 1.93, and 1.56 +/- 0.11 and 9.45 +/- 1.03, respectively. The statistical differences between the four groups and the analysis of the distribution of the parameters of Ca(2+) release and clearance show that there is a continuum from slow to fast, that parallels the MHC continuum from pure type I to pure IIB. However, type IIA fibres behave more like IIX and IIB fibres regarding Ca(2+) release but closer to type I fibres regarding Ca(2+) clearance. In conclusion, we show for the first time the diversity of Ca(2+) transients for the whole continuum of fibre types and correlate this functional diversity with the structural and biochemical diversity of the skeletal muscle fibres.This publication has 64 references indexed in Scilit:
- Low-Affinity Ca2+ Indicators Compared in Measurements of Skeletal Muscle Ca2+ TransientsBiophysical Journal, 2009
- Deconstructing calsequestrin. Complex buffering in the calcium store of skeletal muscleThe Journal of Physiology, 2009
- Reorganized stores and impaired calcium handling in skeletal muscle of mice lacking calsequestrin‐1The Journal of Physiology, 2007
- Events of the excitation–contraction–relaxation (E–C–R) cycle in fast‐ and slow‐twitch mammalian muscle fibres relevant to muscle fatigueActa Physiologica Scandinavica, 1998
- Comparison of calcium release from sarcoplasmic reticulum of slow and fast twitch musclesThe Journal of Membrane Biology, 1991
- Myoplasmic calcium transients in intact frog skeletal muscle fibers monitored with the fluorescent indicator furaptra.The Journal of general physiology, 1991
- Correlation between shortening velocity, force—velocity relation and histochemical fibre-type composition in rat musclesJournal of Muscle Research and Cell Motility, 1990
- Three myosin heavy chain isoforms in type 2 skeletal muscle fibresJournal of Muscle Research and Cell Motility, 1989
- Discrimination between fast- and slow-twitch fibres of guinea pig skeletal muscle using the relative surface density of junctional transverse tubule membraneJournal of Muscle Research and Cell Motility, 1988
- A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye bindingAnalytical Biochemistry, 1976