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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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Superimposed records of force produced by dogfish fibres during activation from relaxed state (activation protocol 1) with temperature change from 5 to 12°C after 8 s of contraction. Records with added Pi are shown as broken lines. The italic numbers indicate the order of the contractions. a For contraction 1 and 3 [Pi] = 2.03 mmol l−1 at 5°C and 2.50 mmol l−1 at 12°C. For contraction 2 [Pi] = 22.03 mmol l−1 at 5°C and 22.50 mmol l−1 at 12°C. b For contraction 1 and 3 [Pi] 22.03 mmol l−1 at 5°C and 22.50 mmol l−1 at 12°C. For contraction 2 [Pi] = 2.03 mmol l−1 at 5°C and 2.50 mmol l−1 at 12°C. See text and Tables 3, 4 for description of estimation of [Pi]. All records in (a) are from the same fibre. Records in (b) are from a different fibre. Heavy vertical bars mark time at which temperature was changed. Horizontal broken lines show measured values of force
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Fig1: Superimposed records of force produced by dogfish fibres during activation from relaxed state (activation protocol 1) with temperature change from 5 to 12°C after 8 s of contraction. Records with added Pi are shown as broken lines. The italic numbers indicate the order of the contractions. a For contraction 1 and 3 [Pi] = 2.03 mmol l−1 at 5°C and 2.50 mmol l−1 at 12°C. For contraction 2 [Pi] = 22.03 mmol l−1 at 5°C and 22.50 mmol l−1 at 12°C. b For contraction 1 and 3 [Pi] 22.03 mmol l−1 at 5°C and 22.50 mmol l−1 at 12°C. For contraction 2 [Pi] = 2.03 mmol l−1 at 5°C and 2.50 mmol l−1 at 12°C. See text and Tables 3, 4 for description of estimation of [Pi]. All records in (a) are from the same fibre. Records in (b) are from a different fibre. Heavy vertical bars mark time at which temperature was changed. Horizontal broken lines show measured values of force

Mentions: Fibres were transferred from pre-activating solution to activating solution at 5°C for 8 s, then to activating solution at 12 or 20°C for 4 s, and finally to relaxing solution at 12 or 20°C. This protocol was repeated three times on each fibre with the order of the added [Pi] (mmol l−1) being for half of the fibres: 0, 20, 0, and for the other half: 20, 0 and 20. Twenty fibres were tested at 5 and 12°C. An additional ten fibres were tested at 5 and 20°C. See Table 1A for solutions and Fig. 1 for example records. The average peak force observed in these experiments with 0 added Pi was 285 ± SEM 7.7 kPa (n = 20 fibres) when the higher temperature was 12°C and 277 ± SEM 8.9 kPa (n = 10 fibres) for 20°C.Fig. 1


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)

Superimposed records of force produced by dogfish fibres during activation from relaxed state (activation protocol 1) with temperature change from 5 to 12°C after 8 s of contraction. Records with added Pi are shown as broken lines. The italic numbers indicate the order of the contractions. a For contraction 1 and 3 [Pi] = 2.03 mmol l−1 at 5°C and 2.50 mmol l−1 at 12°C. For contraction 2 [Pi] = 22.03 mmol l−1 at 5°C and 22.50 mmol l−1 at 12°C. b For contraction 1 and 3 [Pi] 22.03 mmol l−1 at 5°C and 22.50 mmol l−1 at 12°C. For contraction 2 [Pi] = 2.03 mmol l−1 at 5°C and 2.50 mmol l−1 at 12°C. See text and Tables 3, 4 for description of estimation of [Pi]. All records in (a) are from the same fibre. Records in (b) are from a different fibre. Heavy vertical bars mark time at which temperature was changed. Horizontal broken lines show measured values of force
© Copyright Policy
Related In: Results  -  Collection

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

Fig1: Superimposed records of force produced by dogfish fibres during activation from relaxed state (activation protocol 1) with temperature change from 5 to 12°C after 8 s of contraction. Records with added Pi are shown as broken lines. The italic numbers indicate the order of the contractions. a For contraction 1 and 3 [Pi] = 2.03 mmol l−1 at 5°C and 2.50 mmol l−1 at 12°C. For contraction 2 [Pi] = 22.03 mmol l−1 at 5°C and 22.50 mmol l−1 at 12°C. b For contraction 1 and 3 [Pi] 22.03 mmol l−1 at 5°C and 22.50 mmol l−1 at 12°C. For contraction 2 [Pi] = 2.03 mmol l−1 at 5°C and 2.50 mmol l−1 at 12°C. See text and Tables 3, 4 for description of estimation of [Pi]. All records in (a) are from the same fibre. Records in (b) are from a different fibre. Heavy vertical bars mark time at which temperature was changed. Horizontal broken lines show measured values of force
Mentions: Fibres were transferred from pre-activating solution to activating solution at 5°C for 8 s, then to activating solution at 12 or 20°C for 4 s, and finally to relaxing solution at 12 or 20°C. This protocol was repeated three times on each fibre with the order of the added [Pi] (mmol l−1) being for half of the fibres: 0, 20, 0, and for the other half: 20, 0 and 20. Twenty fibres were tested at 5 and 12°C. An additional ten fibres were tested at 5 and 20°C. See Table 1A for solutions and Fig. 1 for example records. The average peak force observed in these experiments with 0 added Pi was 285 ± SEM 7.7 kPa (n = 20 fibres) when the higher temperature was 12°C and 277 ± SEM 8.9 kPa (n = 10 fibres) for 20°C.Fig. 1

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