EurekaMag
+ Translate
+ Most Popular
Sympathetic and visceral nerve blocks
What should be done after bee or wasp stings?
Anti-drool cheiloplasty: clinical results in six dogs
The biology of human starvation: some new insights
Vitamin B12 deficiency as a worldwide problem
Effect of daily gelatin ingestion on human scalp hair
On the nature and role of vivotoxins in plant disease
History of the discovery of vitamins by N. I. Lunin
Preliminary tests with residual sprays against poultry lice
MDU.1, a new mutant chilli variety
A study on compatibility of some insecticides with a fungicide on small cardamom (Elettaria cardamomum Maton.)
The cranial nerves of Mystus seenghala (Sykes)
The effects of prefrontal lobotomy on aggressive behavior in dogs
Human monkeypox: disease pattern, incidence and attack rates in a rural area of northern Zaire
The identity of the lipstick mold of cultivated mushrooms agaricus bisporus
Therapy for acne with saccharomyces boulardii
Advantages and disadvantages of bordeaux mixture and of lime-sulphur used on apples in the growing season
The composition of pampas-grass (Cortaderia argentea.)
Productivity of Pekin x Khaki Campbell ducks
A rapid survey of katydids (Insecta: Orthoptera: Tettigoniidae) of the Foret Classee du Pic de Fon, Guinea
Cranial nerves of Labeo rohita (Ham.)
Evaluating fundamentals of care: The development of a unit-level quality measurement and improvement programme
Life-cycle of the free-living nematode Pontonema vulgare in the White Sea
Grey leaf blight - a new disease of cocoa
Effect of foliar spray of urea and zinc sulphate on yield and fruit quality of Kinnow - 'a mandarin hybrid'

The influence of free calcium on the maximum speed of shortening in skinned frog muscle fibres


The influence of free calcium on the maximum speed of shortening in skinned frog muscle fibres



Journal of Physiology 380: 257-273



ISSN/ISBN: 0022-3751

PMID: 3497264

DOI: 10.1113/jphysiol.1986.sp016284

The influence of [Ca2+] on the maximum velocity of shortening (Vmax) was examined in mechanically skinned Rana pipiens and Rana temporaria fibres using improved force clamps and the slack test techniques. All measurements were made at 7.5 degrees C. At low relative loads (P/P0 less than 0.1), maximally activated R. pipiens fibres shortened more rapidly than did submaximally activated fibres. At higher relative loads, however, little difference in the speed of shortening was observed. Vmax (determined by the slack test) of R. pipiens fibres increased as the level of activation increased. Over sarcomere lengths 1.8-2.1 microns it was 2.28 muscle lengths/s (m.l./s) (S.E. of mean +/- 0.25, n = 5) at 20-35% activation, 2.89 m.l./s (+/- 0.22, n = 7) at 40-60% activation, and 4.18 m.l./s (+/- 0.25, n = 6) at 100% activation. At longer sarcomere lengths (2.2-2.6 microns), higher Vmax values were observed at all levels of activation, but the influence of Ca2+ on Vmax persisted. Vmax was 3.54 m.l./s (+/- 0.41, n = 4) at 20-30% activation and 5.15 m.l./s (+/- 0.22, n = 5) at 100% activation. In R. temporaria fibres, Vmax (determined by force clamps over sarcomere lengths 1.8-2.1 micron) also increased as the level of activation increased, from 3.47 m.l./s (+/- 0.06, n = 6) at 13-29% activation to 5.62 m.l./s (+/- 0.17, n = 6) at 100% activation. Vmax was also determined (using the slack test) in mechanically and chemically skinned rabbit soleus fibres. Vmax at 15 degrees C (1.05 m.l./s, +/- 0.11, n = 5) at full activation decreased by more than 3-fold as the level of activation was reduced to 10%. We conclude that the level of activation influences the Vmax of skinned skeletal muscle fibres. This has now been demonstrated in three different preparations and by a variety of techniques. This effect is most pronounced at low relative loads, and might not be observed if there are experimental limitations which prevent making velocity measurements at low relative loads.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 018170893

Download citation: RISBibTeXText

Related references

The maximum speed of shortening in living and skinned frog muscle fibres. Journal of Physiology 370: 181-199, 1986

Influence of calcium on maximum shortening velocity in skinned muscle fibers of the frog. Federation Proceedings 39(6): ABSTRACT 1884, 1980

The relation between maximum shortening velocity and the magnesium adenosine triphosphate concentration in frog skinned muscle fibres. Journal of Physiology 292: 71P-72P, 1979

The effect of calcium on the maximum speed of shortening in skinned muscle fibers. Biophysical Journal 47(2 Part 2): 288A, 1985

A comparison of order and orientation of crossbridges in rigor and relaxed muscle fibres using fluorescence polarization. Journal of Muscle Research and Cell Motility 4(6): 671-693, 1983

Changes in the maximum speed of shortening of frog muscle fibres early in a tetanic contraction and during relaxation. Journal of Physiology 507: 511-525, 1998

Effects of calcium and ionic strength on shortening velocity and tension development in frog skinned muscle fibres. Journal of Physiology 311: 179-199, 1981

The influence of calcium on shortening velocity of skinned frog muscle cells. Journal of Muscle Research and Cell Motility 4(3): 263-282, 1983

Shortening induced deactivation of skinned fibres of frog and mouse striated muscle. Acta Physiologica Scandinavica 116(2): 189-199, 1982

Modulating factors of calcium-free contraction at low [MgATP]: a physiological study on the steady states of skinned fibres of frog skeletal muscle. Journal of Muscle Research and Cell Motility 19(8): 949-960, 1998

The relation between maximum shortening velocity and the magnesium atp concentration in frog skinned muscle fibers. Journal of Physiology (Cambridge) 292: 71P-72P, 1979

Maximum shortening velocity and coexistence of myosin heavy chain isoforms in single skinned fast fibres of rat skeletal muscle. Journal of Muscle Research and Cell Motility 15(4): 413-419, 1994

Differences in maximum velocity of shortening along single muscle fibres of the frog. Journal of Physiology 365: 147-163, 1985

The maximum velocity of shortening during the early phases of the contraction in frog single muscle fibres. Journal of Muscle Research and Cell Motility 5(5): 503-513, 1984

The effect of calcium on the maximum velocity of shortening in skinned skeletal muscle fibres of the rabbit. Journal of Muscle Research and Cell Motility 3(3): 295-311, 1982