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Effect of phosphate and temperature on force exerted by white muscle fibres from dogfish.

Park-Holohan SJ, West TG, Woledge RC, Ferenczi MA, Barclay CJ, Curtin NA - J. Muscle Res. Cell. Motil. (2010)

Bottom Line: Effects of Pi (inorganic phosphate) are relevant to the in vivo function of muscle because Pi is one of the products of ATP hydrolysis by actomyosin and by the sarcoplasmic reticulum Ca(2+) pump.Pi sensitivity of force produced by dogfish fibres activated from the relaxed state was greater below normal body temperature (12 degrees C for dogfish) in agreement with what is known for other species.The force-temperature relationship for dogfish fibres (intact and permeabilized fibres activated from relaxed) showed that at 12 degrees C, normal body temperature, the force was near to its maximum value.

View Article: PubMed Central - PubMed

Affiliation: Molecular Medicine Section, National Heart and Lung Institute, Sir Alexander Fleming Building, Imperial College London, London, SW7 2AZ, UK.

ABSTRACT
Effects of Pi (inorganic phosphate) are relevant to the in vivo function of muscle because Pi is one of the products of ATP hydrolysis by actomyosin and by the sarcoplasmic reticulum Ca(2+) pump. We have measured the Pi sensitivity of force produced by permeabilized muscle fibres from dogfish (Scyliorhinus canicula) and rabbit. The activation conditions for dogfish fibres were crucial: fibres activated from the relaxed state at 5, 12, and 20 degrees C were sensitive to Pi, whereas fibres activated from rigor at 12 degrees C were insensitive to Pi in the range 5-25 mmol l(-1). Rabbit fibres activated from rigor were sensitive to Pi. Pi sensitivity of force produced by dogfish fibres activated from the relaxed state was greater below normal body temperature (12 degrees C for dogfish) in agreement with what is known for other species. The force-temperature relationship for dogfish fibres (intact and permeabilized fibres activated from relaxed) showed that at 12 degrees C, normal body temperature, the force was near to its maximum value.

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Example records of force produced by dogfish fibres activated from the rigor state at 12°C (activation protocol 2) with (a) increasing and (b) decreasing [Pi]. Italic numbers are the Pi concentrations in units of mmol l−1; broken vertical lines indicate time of solution change. Downward pointing arrows show when force was measured, and the upward pointing arrow shows the baseline from which force was measured. Different fibre in a than b
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Fig2: Example records of force produced by dogfish fibres activated from the rigor state at 12°C (activation protocol 2) with (a) increasing and (b) decreasing [Pi]. Italic numbers are the Pi concentrations in units of mmol l−1; broken vertical lines indicate time of solution change. Downward pointing arrows show when force was measured, and the upward pointing arrow shows the baseline from which force was measured. Different fibre in a than b

Mentions: Fibres were transferred from relaxing solution through the following sequence of solutions: pre-rigor, Ca2+-free rigor, and Ca2+-rigor for about 5 min each. Following this the fibre was transferred to activating solutions with added [Pi] (mmol l−1) 0, 5, 10 and 20 for about 40 s each and then transferred to post-activation relaxing solution. The order in which the different [Pi] were used was varied between experiments. See Table 1B for solutions and Fig. 2 for example records.Fig. 2


Effect of phosphate and temperature on force exerted by white muscle fibres from dogfish.

Park-Holohan SJ, West TG, Woledge RC, Ferenczi MA, Barclay CJ, Curtin NA - J. Muscle Res. Cell. Motil. (2010)

Example records of force produced by dogfish fibres activated from the rigor state at 12°C (activation protocol 2) with (a) increasing and (b) decreasing [Pi]. Italic numbers are the Pi concentrations in units of mmol l−1; broken vertical lines indicate time of solution change. Downward pointing arrows show when force was measured, and the upward pointing arrow shows the baseline from which force was measured. Different fibre in a than b
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2908752&req=5

Fig2: Example records of force produced by dogfish fibres activated from the rigor state at 12°C (activation protocol 2) with (a) increasing and (b) decreasing [Pi]. Italic numbers are the Pi concentrations in units of mmol l−1; broken vertical lines indicate time of solution change. Downward pointing arrows show when force was measured, and the upward pointing arrow shows the baseline from which force was measured. Different fibre in a than b
Mentions: Fibres were transferred from relaxing solution through the following sequence of solutions: pre-rigor, Ca2+-free rigor, and Ca2+-rigor for about 5 min each. Following this the fibre was transferred to activating solutions with added [Pi] (mmol l−1) 0, 5, 10 and 20 for about 40 s each and then transferred to post-activation relaxing solution. The order in which the different [Pi] were used was varied between experiments. See Table 1B for solutions and Fig. 2 for example records.Fig. 2

Bottom Line: Effects of Pi (inorganic phosphate) are relevant to the in vivo function of muscle because Pi is one of the products of ATP hydrolysis by actomyosin and by the sarcoplasmic reticulum Ca(2+) pump.Pi sensitivity of force produced by dogfish fibres activated from the relaxed state was greater below normal body temperature (12 degrees C for dogfish) in agreement with what is known for other species.The force-temperature relationship for dogfish fibres (intact and permeabilized fibres activated from relaxed) showed that at 12 degrees C, normal body temperature, the force was near to its maximum value.

View Article: PubMed Central - PubMed

Affiliation: Molecular Medicine Section, National Heart and Lung Institute, Sir Alexander Fleming Building, Imperial College London, London, SW7 2AZ, UK.

ABSTRACT
Effects of Pi (inorganic phosphate) are relevant to the in vivo function of muscle because Pi is one of the products of ATP hydrolysis by actomyosin and by the sarcoplasmic reticulum Ca(2+) pump. We have measured the Pi sensitivity of force produced by permeabilized muscle fibres from dogfish (Scyliorhinus canicula) and rabbit. The activation conditions for dogfish fibres were crucial: fibres activated from the relaxed state at 5, 12, and 20 degrees C were sensitive to Pi, whereas fibres activated from rigor at 12 degrees C were insensitive to Pi in the range 5-25 mmol l(-1). Rabbit fibres activated from rigor were sensitive to Pi. Pi sensitivity of force produced by dogfish fibres activated from the relaxed state was greater below normal body temperature (12 degrees C for dogfish) in agreement with what is known for other species. The force-temperature relationship for dogfish fibres (intact and permeabilized fibres activated from relaxed) showed that at 12 degrees C, normal body temperature, the force was near to its maximum value.

Show MeSH
Related in: MedlinePlus