Biophysical Journal 56: 809-816 (1989)
© 1989 the Biophysical Society

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bershitsky SYu, Articles by Tsaturyan, A K Search for Related Content PubMed PubMed Citation Articles by Bershitsky SYu, Articles by Tsaturyan, A K

Effect of joule temperature jump on tension and stiffness of skinned rabbit muscle fibers.

Laboratory of Biophysics, Sverdlovsk Institute of Industrial Hygiene and Occupational Diseases, Soviet Union.

ABSTRACT

The effects of a temperature jump (T-jump) from 5-7 degrees C to 26-33 degrees C were studied on tension and stiffness of glycerol-extracted fibers from rabbit psoas muscle in rigor and during maximal Ca2+ activation. The T-jump was initiated by passing an alternating current pulse (30 kHz, up to 2.5 kV, duration 0.2 ms) through a fiber suspended in air. In rigor the T-jump induces a drop of both tension and stiffness. During maximal activation, the immediate stiffness dropped by (4.4 +/- 1.6) x 10(-3)/1 degree C (mean + SD) in response to the T-jump, and this was followed by a monoexponential stiffness rise by a factor of 1.59 +/- 0.14 with a rate constant ks = 174 +/- 42 s-1 (mean +/- SD, n = 8). The data show that the fiber stiffness, determined by the cross-bridge elasticity, in both rigor and maximal activation is not rubber-like. In the activated fibers the T-jump induced a biexponential tension rise by a factor of 3.45 +/- 0.76 (mean +/- SD, n = 8) with the rate constants 500-1,000 s-1 for the first exponent and 167 +/- 39 s-1 (mean +/- SD, n = 8) for the second exponent. The data are in accordance with the assumption that the first phase of the tension transient after the T-jump is due to a force-generating step in the attached cross-bridges, whereas the second one is related to detachment and reattachment of cross-bridges.

This article has been cited by other articles:

				K. W. Ranatunga, M. E. Coupland, G. J. Pinniger, H. Roots, and G. W. Offer Force generation examined by laser temperature-jumps in shortening and lengthening mammalian (rabbit psoas) muscle fibres J. Physiol., November 15, 2007; 585(1): 263 - 277. [Abstract] [Full Text] [PDF]

				M. E. Coupland, G. J. Pinniger, and K. W. Ranatunga Endothermic force generation, temperature-jump experiments and effects of increased [MgADP] in rabbit psoas muscle fibres J. Physiol., September 1, 2005; 567(2): 471 - 492. [Abstract] [Full Text] [PDF]

				S. Y. Bershitsky and A. K. Tsaturyan The elementary force generation process probed by temperature and length perturbations in muscle fibres from the rabbit J. Physiol., May 1, 2002; 540(3): 971 - 988. [Abstract] [Full Text] [PDF]