PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “SARTORIUS MUSCLE”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources
PubMed1968

Selective disruption of the sarcotubular system in frog sartorius muscle. A quantitative study with exogenous peroxidase as a marker.

Skeletal muscles which have been soaked for 1 hr in a glycerol-Ringer solution and then returned to normal Ringer solution have a disrupted sarcotubular system. The effect is associated with the return to Ringer's since muscles have normal fine structure while still in glycerol-Ringer's. Karnovsky's peroxidase method was found to be a very reliable marker of extracellular space, filling 98.5% of the tubules in normal muscle. It was interesting to note that only 84.1% of the sarcomeres in normal muscle have transverse tubules. The sarcotubular system was essentially absent from glycerol-treated muscle fibers, only 2 % of the tubular system remaining connected to the extracellular space; the intact remnants were stumps extending only a few micra into the fiber. Thus, glycerol-treated muscle fibers provide a preparation of skeletal muscle with little sarcotubular system. Since the sarcoplasmic reticulum is not destroyed and the sarcolemma and myofilaments are intact in this preparation, of the properties of the sarcolemma may thus be separated from those of the tubular system.

Animals↗
PubMed1958

The effect of enzyme inhibitors on the resting potential and on the ion distribution of the sartorius muscle of the frog.

Isolated frog sartorii were exposed for 30 minutes to HETP-an irreversible anti-cholinesterase, and were then soaked in Ringer's at 15 degrees C. for 16 hours. At the end of the period of soaking the mean resting potential of the muscle fibers was only 29 mv. The decrease in the resting potential of the HETP-treated muscles was accompanied by a loss of potassium and a gain in sodium by the muscles. The effect of anticholinesterases on sodium extrusion was studied by incubating the muscles in a Ringer's containing half of the normal amount of sodium. The muscles respond by extruding sodium against a concentration gradient into the external medium. Sodium extrusion was blocked by prior exposure of the muscle to HETP, and reversibly blocked by exposure to physostigmine. The inhibition of sodium extrusion by physostigmine was correlated with the inhibition of the intracellular cholinesterase. Sodium extrusion was also blocked by high concentrations of 2-methyl-1,4-napthaquinone 8-sulfonic acid and by alpha-ketoglutarate, which are known to inhibit choline acetylase in vitro. But sodium extrusion was not affected by a third inhibitor of choline acetylase, phenobarbital. Sodium extrusion was unaffected by KCN and partially blocked by IAA. The IAA block was eliminated by the addition of pyruvate. It is concluded that either glycolysis or oxidative metabolism can furnish the energy needed for sodium extrusion.

Animals↗
PubMed1959

The dimensions of the extracellular space in sartorius muscle.

A survey has been made of the amount of muscle water available to inulin, sucrose, and radioiodinated human serum albumin (RISA). The percentage spaces available to the three molecules are of the same order of magnitude, but the sucrose space > inulin space > albumin space. The kinetics of influx and efflux of RISA have been studied, and it appears that a small part of the albumin may be adsorbed in the extracellular phase. Nevertheless the albumin space would appear to give the best index of the extracellular volume. The scatter in values found for the extracellular space by all methods is very great, ranging from 8 to 40 per cent and renders invalid the use of a mean value for the calculation of intracellular concentrations. The variation within paired muscles is less than between pairs, provided the tissue has undergone no volume change. Increase in total muscle volume when the muscle is placed in a hypotonic solution leads to a decrease in the size of the extracellular space.

Electrolytes↗
PubMed1966

Activation heat in frog sartorius muscle.

Upon excitation of a muscle with two stimuli and variation of the interval between them up to the end of the period of full mechanical fusion, an increment of the isometric heat over that found in a single twitch is obtained. This is a good approximation to the activation heat, directly at 0 degrees C, or after certain corrections which become important at higher temperature. The activation heat so found is independent of the muscle length and nearly independent of temperature. It is increased by nitrate and caffeine.

Animals↗
PubMed1967

Theoretical series elastic element length in Rana pipiens sartorius muscles.

Assuming a two component system for the muscle, a series elastic element and a contractile component, the analyses of the isotonic and isometric data points were related to obtain the series elastic stiffness, dP/dl(s), from the relation, See PDF for Equation From the isometric data, dP/dt was obtained and shortening velocity, v, was a result of the isotonic experiments. Substituting (P(0) - P)/T for dP/dt and (P(0) - P)/(P + a) times b for v, dP/dl(s) = (P + a) /bT, where P < P(0), and a, b are constants for any lengths l </= l(0) (Matsumoto, 1965). If the isometric tension and the shortening velocity are recorded for a given muscle length, l(0), although the series elastic, l(s), and the contractile component, l(c), are changing, the total muscle length, l(0) remains fixed and therefore the time constant, T. Integrating, See PDF for Equation the stress-strain relation for the series elastic element, See PDF for Equation is obtained; l(sc0) - l(s) + l(c0)where l(co) equals the contractile component length for a muscle exerting a tension of P(0). For a given P/P(0), l(s) is uniquely determined and must be the same whether on the isotonic or isometric length-tension-time curve. In fact, a locus on one surface curve can be associated with the corresponding locus on the other.

Animals↗
PubMed1969

Capacitance of the surface and transverse tubular membrane of frog sartorius muscle fibers.

The passive electrical properties of glycerol-treated muscle fibers, which have virtually no transverse tubules, were determined. Current was passed through one intracellular microelectrode and the time course and spatial distribution of the resulting potential displacement measured with another. The results were analyzed by using conventional cable equations. The membrane resistance of fibers without tubules was 3759 +/- 331 ohm-cm(2) and the internal resistivity 192 ohm-cm. Both these figures are essentially the same as those found in normal muscle fibers. The capacitance of the fibers without tubules is strikingly smaller than normal, being 2.24 +/- 0.14 microF/cm(2). Measurements were also made of the passive electrical properties of fibers in a Ringer solution containing 400 mM glycerol (which is used in the preparation of glycerol-treated fibers). The membrane resistance and capacitance are essentially normal, but the internal resistivity is somewhat reduced. These results show that glycerol in this concentration does not directly affect the membrane capacitance. Thus, the figure for the capacitance of glycerol-treated fibers, which agrees well with previous estimates made by different techniques, represents the capacitance of the outer membrane of the fiber. Estimates of the capacitance per unit area of the tubular membrane are made and the significance of the difference between the figures for the capacitance of the surface and tubular membrane is discussed.

Action Potentials↗
PubMed1976

Density and distribution of tetrodotoxin receptors in normal and detubulated frog sartorius muscle.

Tetrodotoxin (TTX) binding was measured in muscles which were either in normal condition or which had been "detubulated" by glycerol-induced osmotic shock. In both cases the binding of TTX was found to saturate at high TTX concentrations. Maximum binding in normal fibers was 35 pmol/g wet weight, and that figure was reduced to 16 pmol/g after glycerol treatment. The dissociation constant for binding to the surface membrane was 3 nM, which is the range of values obtained by electrophysiological measurements of the effect of TTX on the maximum rate of rise of the action potential. The results suggest that the dissociation constant in the transverse tubules may be higher than that in the surface. Control experiments indicate that the effects of glycerol treatment are limited to the accessibility of the receptors to the toxin and result in no alteration of the affinity of the binding site. TTX receptors in the transverse tubules may be recovered after glycerol treatment by homogenization of the fibers. The measurements suggest that the density of sodium channels in surface membrane is about 175/muM2 and that in the transverse tubular membrane is 41-52/mum2.

Action Potentials↗
PubMed1970

Effects of sulphydryl inhibitors on frog sartorius muscle: N-ethylmaleimide.

1. The characteristic action of the -SH inhibitor, N-ethylmaleimide (NEM), is muscle rigour. The dose-response curve indicates a biphasic effect with maximum rigour tension produced by 1.0 mM NEM; beyond 1.0 mM there was an inverse relationship between dose and response.2. NEM produces a membrane depolarization unrelated to rigour development.3. NEM causes a sustained increase in (45)Ca efflux from whole muscle. Pretreatment of a muscle with ethylenediamine tetra-acetic acid (EDTA, 5 mM) to remove membrane calcium does not alter the NEM induced (45)Ca efflux.4. It is suggested that the primary site of NEM action is inhibition of calcium uptake by the sarcoplasmic reticulum thereby producing rigour. At concentrations above 1.0 mM, NEM may affect the myofilaments.

Action Potentials↗