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Effect of taurine on sarcoplasmic reticulum function and force in skinned fast‐twitch skeletal muscle fibres of the rat
Author(s) -
Bakker Anthony J.,
Berg Helen M.
Publication year - 2002
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2001.012872
Subject(s) - taurine , caffeine , endoplasmic reticulum , chemistry , skeletal muscle , depolarization , extensor digitorum longus muscle , fast twitch muscle , medicine , endocrinology , biophysics , biochemistry , biology , amino acid
We examined the effect of taurine on depolarisation‐induced force responses and sarcoplasmic reticulum (SR) function in mechanically skinned skeletal muscle fibres from the extensor digitorum longus (EDL) of the rat. Taurine (20 m m ) produced a small but significant ( P < 0.01) decrease in the sensitivity of the contractile apparatus to Ca 2+ (increase in the [Ca 2+ ] corresponding to 50 % of maximum force of about 7 %; n = 10) and in maximum force (92.0 ± 1.0 % of controls) in the skinned fibres. Taurine had no statistically significant effect on the slope of the force‐pCa curve. Depolarisation‐induced force responses in the skinned fibres were markedly increased in peak value by 20 m m taurine, to 120.8 ± 5.3 % of control measurements ( P = 0.0006, n = 27). Taurine (20 m m ) significantly increased the SR Ca 2+ accumulation in the skinned fibres by 34.6 ± 9.3 % compared to control conditions (measured by comparing the integral of caffeine contractures in fibres previously loaded with Ca 2+ in the absence or presence of taurine; P = 0.0014, n = 10). Taurine (20 m m ) also increased both the peak and rate of rise of caffeine‐induced force responses in the fibres by 29.2 ± 9.7 % ( P = 0.0298, n = 6) and 27.6 ± 8.9 % ( P = 0.037), respectively, compared with controls. This study shows that taurine is a modulator of contractile function in mammalian skeletal muscle. Taurine may increase the size of depolarisation‐induced force responses by augmenting SR Ca 2+ accumulation and release.