The Time Course of the Loss and Recovery of Contracture Ability in Frog Striated Muscle Following Exposure to Ca-Free Solutions

Milligan, John V.

doi:10.1085/jgp.48.5.841

Cited by 21 publications

(15 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These data are consistent with diffusion from a cylinder radius 150 ,tm of a substance with a diffusion coefficient 2x 10-6 cm2/sec (Milligan, 1965;see Jacobs, 1967). A second method of analysing the extracellular calcium content in normal muscles employed the use of atomic absorption spectrophotometry.…”

supporting

confidence: 67%

Calcium content and exchange in frog skeletal muscle.

Kirby¹,

Lindley²,

Picken³

1975

The Journal of Physiology

View full text Add to dashboard Cite

Calcium content and exchange in frog ELD IV muscle were examined employing the efflux technique. 2. Muscle calcium was found to exchange with four time constants, 21‐5 sec 2‐7, 32 and 1244 min. 3. All calcium was found to be exchangeable with more than half the total amount residing in an extracellular compartment. 4. Results obtained from ELD IV muscles and single fibres were identical. 5. Muscle calcium content was found to remain constant up to 20 hr in vitro. 6. Extra exchange of calcium occurs upon contraction. This extra exchange appears to occur in the most slowly exchanging component. 7. The data are discussed in relation to morphological and autoradiographic findings and a model of calcium exchange in skeletal muscle is presented.

show abstract

supporting

confidence: 67%

Calcium content and exchange in frog skeletal muscle.

Kirby¹,

Lindley²,

Picken³

1975

The Journal of Physiology

View full text Add to dashboard Cite

show abstract

“…Tension developed by the muscle in response to elevated K solutions or to caffeine (Eastman Kodak) was measured by a strain gauge and recorded with a Grass pen recorder. The contractures were compared by measuring the area under the contracture curve (Milligan, 1965).…”

Section: Methodsmentioning

confidence: 99%

The effect of the replacement of calcium by strontium on excitation‐contraction coupling in frog skeletal muscle

Edwards¹,

Lorković²,

Weber³

1966

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. In frog skeletal muscle strontium can replace calcium in potassium contractures for 5 hr, though it is less effective than Ca. Sr can restore the responsiveness to K after it had been lost in the presence of Mn.2. Muscles refractory to caffeine following repeated exposure to it in the absence of Ca, recover in part following addition of Sr. 3. The uptake of 85Sr was increased during mechanical activity, whereas the uptake of 58Co was not changed. Resting uptake of 58Co was 3-4 times greater than that of 85Sr.4. Sr fully activated the myofibrillar adenosine triphosphatase (ATPase), though its affinity was about 30 times less than Ca.5. The sarcoplasmic reticulum took up Sr, though less effectively than Ca.

show abstract

“…6). This KMeSO3 medium should depolarize cell membranes without causing appreciable swelling (15). When the normal Cl-concentration was reintroduced, however, a typical increase in intensity fluctuations was observed, apparently due to the entry of KCI (and water) into the cells.…”

Section: Resultsmentioning

confidence: 96%

Effect of increased potassium concentrations on particle motion within a neurosecretory structure.

Englert¹,

Edwards²

1977

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Intensity fluctuation spectroscopy was used to detect particle motion within the pericardial organ of the crab Carcinus while it was perfused with media with increased potassium concentrations. Replacement of some or all of the sodium ions of the normal medium with potassium ions caused a graded increase in motion. Evidence is presented which indicates that this effect is not a consequence of membrane depolarization or calcium ion influx, but is due to the flux of potassium chloride and water into the cytoplasm of the cells. The observation of Shaw and Newby has been confirmed and extended by Piddington and Sattelle (5). They found, however, that omission of calcium ions from the medium had no effect on the potassium response (6). Despite this, they nevertheless attributed the scattering change to calcium entry.We have investigated this phenomenon to determine whether it has any relevance to the mechanism of neurotransmitter release. The pericardial organ of the crab Carcinus was used. This is a specialized neurosecretory structure, the cortex of which is packed tightly with neurosecretory endings containing a variety of granules and vesicles (7). It usually has a bluish color when viewed under a dissecting lamp, probably due to light scattering by the granular inclusions of the nerve endings (8). METHODSSpecimens of Carcinus were obtained from the Marine Biological Laboratory at Woods Hole and kept in a tank of artificial sea water at about 15'C. The pericardial organ was dissected from an animal in artificial sea water and transferred to a microscope slide to which it was fastened with Vaseline. The microscope slide formed the bottom of a perfusion chamber which could be covered and sealed with a cover slip. This chamber was then mounted on the stage of a specially modified Zeiss WL microscope (Fig. 1).This microscope permits observation of preparations with the incandescent illuminator of the microscope as well as with laser light. The beam of a 4-mW He/Ne laser (Coherent Radiation model 80) passes through a lens and is reflected from a half-silvered mirror and focused onto the back focal plane of the microscope condenser (numerical aperture = 1.4). The beam then passes through the preparation at an angle determined by the lateral displacement of the beam off the optical axis of the microscope (9). This angle can be adjusted between 0°and almost 90°by means of the micrometer drive on the lens-mirror assembly.An iris diaphragm in the image plane of the microscope can limit the field to an area 27 gam in diameter (using a 40X objective). This diaphragm and the image of the preparation can be observed through an ocular or, by removing a mirror from the system, the light scattered from the preparation can be passed through a pair of lenses that bring the back focal plane of the microscope objective (40X, numerical aperture = 0.65) to focus on an aperture in front of the cathode of a photomultiplier tube. The position of this aperture in the back focal plane determines the angle at which light is collected...

show abstract

The Time Course of the Loss and Recovery of Contracture Ability in Frog Striated Muscle Following Exposure to Ca-Free Solutions

Cited by 21 publications

References 20 publications

Calcium content and exchange in frog skeletal muscle.

Calcium content and exchange in frog skeletal muscle.

The effect of the replacement of calcium by strontium on excitation‐contraction coupling in frog skeletal muscle

Effect of increased potassium concentrations on particle motion within a neurosecretory structure.

Contact Info

Product

Resources

About