Received June 13, 2001
Accepted after revision September 10, 2001

Effect of taurine on sarcoplasmic reticulum function and force in skinned fast-twitch skeletal muscle fibres of the rat

¹ Department of Physiology, The University of Western Australia, Nedlands, WA 6907, Australia

^* To whom correspondence should be addressed.

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 mM) produced a small but significant (P < 0.01) decrease in the sensitivity of the contractile apparatus to Ca²⁺ (increase in the [Ca²⁺] 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 mM taurine, to 120.8 ± 5.3 % of control measurements (P = 0.0006, n = 27). Taurine (20 mM) significantly increased the SR Ca²⁺ 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 Ca²⁺ in the absence or presence of taurine; P = 0.0014, n = 10). Taurine (20 mM) 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 Ca²⁺ accumulation and release.

This article has been cited by other articles:

				R. Han, T. Suizu, M. D. Grounds, and A. J. Bakker Effect of indomethacin on force responses and sarcoplasmic reticulum function in skinned skeletal muscle fibers and cytosolic [Ca2+] in myotubes Am J Physiol Cell Physiol, October 1, 2003; 285(4): C881 - C890. [Abstract] [Full Text] [PDF]

				N. Ortenblad, J. F. Young, N. Oksbjerg, J. H. Nielsen, and I. H. Lambert Reactive oxygen species are important mediators of taurine release from skeletal muscle cells Am J Physiol Cell Physiol, June 1, 2003; 284(6): C1362 - C1373. [Abstract] [Full Text] [PDF]