The Refractory Period and the Duration of the Plateau of the Active State in Frog Skeletal Muscle

1973 ◽  
Vol 51 (12) ◽  
pp. 966-975
Author(s):  
N. F. Clinch ◽  
V. Tennant
Keyword(s):  
Skeletal Muscle ◽  
Electrical Properties ◽  
Refractory Period ◽  
Mechanical Response ◽  
State Theory ◽  
Active State ◽  
Isometric Contractions ◽  
Frog Skeletal Muscle ◽  
Plateau Region ◽  
Measurement Artifact

Isometric contractions of frog sartorii in response to paired stimuli (I ms apart) were compared with isometric twitches following single shocks in order to find the time of the first detectable mechanical response to the second shock (ts). For I > 25 ms at 0°, ts = 0.99 I + 13.3 ms; while for I < 25 ms, ts was found to be independent of I. Electrical recording from the muscle surface showed that for I < 25 ms, the second action potential fell within the relative refractory period of the first. The plateau region of the ts–I plot is consistent with the active state theory, but can also be interpreted as (a) a measurement artifact, or (b) revealing electrical properties of the membrane rather than a property of the contractile mechanism itself.

scholarly journals GRAPHICAL ANALYSIS AND EXPERIMENTAL DETERMINATION OF THE ACTIVE STATE IN FROG SKELETAL MUSCLE

1973 ◽  
Vol 23 (2) ◽  
pp. 217-240 ◽  
Author(s):  
Hidenobu MASHIMA ◽  
Kenzo AKAZAWA ◽  
Hiroki KUSHIMA ◽  
Katsuhiko FUJII
Keyword(s):  
Skeletal Muscle ◽  
Experimental Determination ◽  
Graphical Analysis ◽  
Active State ◽  
Frog Skeletal Muscle

Ultra-Rapid Freezing of Isolated Skeletal Muscle Fibers

1977 ◽  
Vol 35 ◽  
pp. 576-577
Author(s):  
Joachim R. Sommer ◽  
Nancy R. Wallace
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Granular Material ◽  
Nuclear Envelope ◽  
Intracellular Calcium ◽  
Ruthenium Red ◽  
Threshold Concentration ◽  
Rapid Freezing ◽  
Frog Skeletal Muscle ◽  
Electrical Isolation

After Howell (1) had shown that ruthenium red treatment of fixed frog skeletal muscle caused collapse of the intermediate cisternae of the sarcoplasmic reticulum (SR), forming a pentalaminate structure by obi iterating the SR lumen, we demonstrated that the phenomenon involves the entire SR including the nuclear envelope and that it also occurs after treatment with other cations, including calcium (2,3,4).From these observations we have formulated a hypothesis which states that intracellular calcium taken up by the SR at the end of contraction causes the M rete to collapse at a certain threshold concentration as the first step in a subsequent centrifugal zippering of the free SR toward the junctional SR (JSR). This would cause a) bulk transport of SR contents, such as calcium and granular material (4) into the JSR and, b) electrical isolation of the free SR from the JSR.

Electron Probe Analysis of Muscle

1982 ◽  
Vol 40 ◽  
pp. 398-401
Author(s):  
A. V. Somlyo ◽  
H. Shuman ◽  
A. P. Somlyo
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Resting State ◽  
Binding Sites ◽  
Electron Probe ◽  
Frog Skeletal Muscle ◽  
Electron Probe Analysis ◽  
Probe Analysis

Electron probe analysis of frozen dried cryosections of frog skeletal muscle, rabbit vascular smooth muscle and of isolated, hyperpermeab1 e rabbit cardiac myocytes has been used to determine the composition of the cytoplasm and organelles in the resting state as well as during contraction. The concentration of elements within the organelles reflects the permeabilities of the organelle membranes to the cytoplasmic ions as well as binding sites. The measurements of [Ca] in the sarcoplasmic reticulum (SR) and mitochondria at rest and during contraction, have direct bearing on their role as release and/or storage sites for Ca in situ.

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