Effects of step changes in pH on isometric tetanic tension of toad sartorius muscle

Jm, Renaud; Stevens, E. D.

doi:10.1139/y83-127

Cited by 5 publications

(2 citation statements)

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“…Throughout this paper the muscle length that produced maximum isometric force is referred to as Lo. Then either plie was left unchanged (high pI-I~ = 7.9) or was decreased (low pI-I~ = 6.5) and the muscle was superfused for a further 40min (Renaud & Stevens, 1983) to allow for pli equilibration before the work measurements..…”

Section: Methodsmentioning

confidence: 99%

Effect of pH and stimulus phase on work done by isolated frog sartorius muscle during cyclical contraction

Stevens

1988

J Muscle Res Cell Motil

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Work per cycle was calculated in isolated frog sartorius muscle by measuring force as the activated muscle was subjected to sinusoidal length changes. Work per cycle was calculated from the area of the loop formed when force was plotted against length. Measurements were made at 20 degrees C using physiological solutions with high pHe (7.9 or low pHe (6.6). Net work done per cycle was positive when the muscle was activated during the shortening phase of the length cycle. Maximum work done increased as excursion amplitude increased and was about 17Jkg-1 at a strain of 12% (i.e. Lo +/- 6%) at a cycle frequency of 2 Hz. Maximum power was 35 W kg-1 and was about 25% less at the lower pHe. Power measured in this way is much less than the value calculated from force-velocity curves. However, power calculated from force-velocity curves neglects the time that the muscle must be inactive during locomotion. Thus the measurements of the present study are realistic relative to actual mechanical power output during locomotion.

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Section: Methodsmentioning

confidence: 99%

Effect of pH and stimulus phase on work done by isolated frog sartorius muscle during cyclical contraction

Stevens

1988

J Muscle Res Cell Motil

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“…[19][20][21] In vertebrates, CO 2 has been used by muscle physiologists to change intracellular pH (pH i ) because it penetrates the sarcolemma with ease. 22 Thus, it seems likely that its use to sedate/anesthetize/euthanize is due to the fact that it penetrates cell membranes with ease and decreases pH i. Most interestingly, in amphibian muscle, a decrease in pH i has an effect similar to that of tricaine; it nearly eliminates inactivation of voltage gated Nachannels.…”

Section: Discussionmentioning

confidence: 99%

Effect of TRIS and Bicarbonate as Buffers on Anesthetic Efficacy of Tricaine Methane Sulfonate in Zebrafish (Danio rerio)

2014

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Tricaine methane sulfonate (TMS), often called MS-222, is the most common anesthetic used with fishes. Because it is very acidic (pKa about 3) it must be neutralized especially when used in soft fresh water. Much of the literature on fish anesthetics recommends neutralizing with bicarbonate. However, much of the zebrafish literature uses the protocol in "The Zebrafish Book" that recommends neutralizing with TRIS. Three considerations when comparing these buffers are: first, TRIS has the advantage that the pH tends to remain constant, whereas the pH of solutions containing bicarbonate tends to increase as CO2 diffuses from the water to air; second, the CO2 produced by bicarbonate may have some sedative effects in and of itself; and third, there is some evidence that the efficacy of TMS changes with pH. In the present study, we compared the efficacy of TMS using these two buffers and show that there is no substantial difference in anesthetic properties in zebrafish.

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Effects of inhibiting carbonic anhydrase on isometric contraction of frog skeletal muscle.

Scheid¹,

Siffert²

1985

The Journal of Physiology

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SUMMARY1. Carbonic anhydrase (CA) activity was determined in a homogenate of frog skeletal muscle by measuring the kinetics of CO2 hydration in a pH stopped-flow apparatus.2. The results suggest that frog skeletal muscle contains a high-activity CA with properties similar to those ofthe isoenzyme CA II found in white skeletal muscle tissue of the rabbit.3. In an attempt to assess the functional significance of CA in skeletal muscle, the maximal isometric force of frog gastrocnemius muscle was measured in response to direct or indirect (ischiadic nerve) single-pulse electrical stimulation before (control) and after exposing the muscle to various concentrations of the specific carbonic anhydrase inhibitors, ethoxzolamide, acetazolamide, and methazolamide.4. In the range of ethoxzolamide concentration between 10-9 and 10-6 M, maximal isometric force with indirect supramaximal stimulation declined progressively with inhibitor concentration to less than 10 % of the control value. Acetazolamide and methazolamide were less effective in that concentrations of above 10-4 M were necessary to inhibit maximum isometric force by 50 %.5. Even at the highest ethoxzolamide concentration used (10-6 M), no effect was observed either on the amplitude of the compound nerve action potential or on the conduction velocity of group I fibres in the ischiadic nerve, suggesting that ethoxzolamide did not affect the mechanisms responsible for spike generation or conduction in the motor fibres.6. With direct supramaximal stimulation of the gastrocnemius muscle, no effects on maximal isometric force were observed of CA inhibition by any of the inhibitors used.7. The results suggest that CA acts on the neuromuscular transmission. The exact site and mechanism of action are unknown.

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Effects of step changes in pH on isometric tetanic tension of toad sartorius muscle

Cited by 5 publications

References 1 publication

Effect of pH and stimulus phase on work done by isolated frog sartorius muscle during cyclical contraction

Effect of pH and stimulus phase on work done by isolated frog sartorius muscle during cyclical contraction

Effect of TRIS and Bicarbonate as Buffers on Anesthetic Efficacy of Tricaine Methane Sulfonate in Zebrafish (Danio rerio)

Effects of inhibiting carbonic anhydrase on isometric contraction of frog skeletal muscle.

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