Potassium redistribution and water movement in crayfish muscle fibers

1972 ◽  
Vol 80 (3) ◽  
pp. 267-283 ◽  
Author(s):  
George M. Katz ◽  
John P. Reuben ◽  
MacBerman ◽  
Philip B. Dunham
Keyword(s):  
Water Movement ◽  
Muscle Fibers ◽  
Crayfish Muscle

scholarly journals Water Transfer and Cell Structure in Isolated Crayfish Muscle Fibers

1964 ◽  
Vol 47 (6) ◽  
pp. 1141-1174 ◽  
Author(s):  
John P. Reuben ◽  
Lucien Girardier ◽  
Harry Grundfest
Keyword(s):  
Membrane Potential ◽  
Water Movement ◽  
Cell Structure ◽  
Muscle Fibers ◽  
Electron Microscopic ◽  
Transverse Tubular System ◽  
Crayfish Muscle ◽  
Osmotic Water ◽  
Electrophysiological Measurements ◽  
Time Courses

Changes in volume of crayfish single muscle fibers in response to changes in ionic or electrical conditions have been studied in conjunction with electrophysiological measurements and electron microscopic examinations. The occurrence of at least three mechanisms of water movements is revealed, two being processes which are superimposed on the normal osmotic water movement that results from a change in the concentration of solute in the medium. Differences between the time courses of the changes in volume and potential on changing Ki/Ko indicate that water may be distributed unequally for a time within compartments of the fiber. Electron micrographs reveal a selective accumulation of water at the periphery of the fiber under certain conditions. A correlation of H2O transfer with a change in membrane potential is apparent in crayfish muscle fibers and is probably due to electroosmotic effects. Electrokinetic water movements are produced whenever the membrane potential is changed to a considerable degree by changing the level of K and/or Cl in the medium, or by applying currents with an intracellular microelectrode. Depolarizations cause shrinkage. Hyperpolarizations or repolarizations cause swelling. The volume changes are independent of the occurrence or absence of swelling in the anion-permselective transverse tubular system. They indicate that the fiber membrane along the surface is heterogeneous, not only with respect to the signs of its fixed charge sites, but also with respect to the sizes and relative permselectivities of these charged channels.

Alterations in intramuscular water movement associated with mechanical changes in human skeletal muscle fibers: an evaluation using magnetic resonance diffusion-weighted imaging and B-mode ultrasonography

2011 ◽  
Vol 52 (9) ◽  
pp. 1003-1008 ◽  
Author(s):  
Osamu Yanagisawa ◽  
Toshiyuki Kurihara ◽  
Toru Fukubayashi
Keyword(s):  
Magnetic Resonance ◽  
Ankle Joint ◽  
Structural Changes ◽  
Water Movement ◽  
Morphological Changes ◽  
Muscle Fibers ◽  
Medial Gastrocnemius ◽  
Plantar Flexors ◽  
Diffusion Weighted Images ◽  
Diffusion Weighted

Background Intramuscular water movement is expected to be affected by the mechanical changes of the muscle fibers. However, the effect of changes in fiber length (FL) and pennation angle (PA) on the water movement has not been sufficiently investigated in human skeletal muscles. Purpose To determine the relationship between intramuscular water movement and the mechanical changes in human muscle fibers. Material and Methods Axial magnetic resonance diffusion-weighted images of the right leg (eight men) were taken using a 1.5-Tesla device with the ankle joint maximally dorsiflexed and maximally plantar flexed. The apparent diffusion coefficient (ADC) values of both the dorsiflexors (the superficial and deep parts of the tibialis anterior) and the plantar flexors (medial gastrocnemius and soleus) were calculated along three orthogonal axes (S-I: superior-to-inferior, A-P: anterior-to-posterior, and R-L: right-to-left). FL and PA of both muscle groups were also calculated from longitudinal B-mode ultrasound images with the ankle joint maximally dorsiflexed and plantar flexed. Results There was a significant increase in the ADC in superficial ( P < 0.05) and deeP ( P < 0.05) parts of the dorsiflexors in the S-I direction when the ankle was plantar flexed and in the A-P and R-L directions when the ankle was dorsiflexed ( P < 0.05). The plantar flexors showed significantly elevated ADC in the S-I direction when the ankle was dorsiflexed ( P < 0.05), and in the A-P and R-L directions when the ankle was plantar flexed ( P < 0.05). The dorsiflexors also showed significantly increased PA and decreased FL values when the ankle was dorsiflexed ( P < 0.05). The plantar flexors displayed similar morphological changes when the ankle was plantar flexed ( P < 0.05). Conclusion Water diffusion is affected by structural changes in the long axis of the muscle fibers, namely the changes in PA and FL.

Fast BK-Type Channel Mediates the Ca2+-Activated K+ Current in Crayfish Muscle

1999 ◽  
Vol 82 (4) ◽  
pp. 1655-1661 ◽  
Author(s):  
Alfonso Araque ◽  
Washington Buño
Keyword(s):  
Electrical Activity ◽  
Single Channel ◽  
Muscle Fibers ◽  
Ionic Channels ◽  
Bk Channels ◽  
Intrinsic Properties ◽  
Open Probability ◽  
Crayfish Muscle ◽  
Fast Activation ◽  
Inside Out

The role of the Ca2+-activated K+ current ( I K(Ca)) in crayfish opener muscle fibers is functionally important because it regulates the graded electrical activity that is characteristic of these fibers. Using the cell-attached and inside-out configurations of the patch-clamp technique, we found three different classes of channels with properties that matched those expected of the three different ionic channels mediating the depolarization-activated macroscopic currents previously described (Ca2+, K+, and Ca2+-dependent K+ currents). We investigated the properties of the ionic channels mediating the extremely fast activating and persistent I K(Ca). These voltage- and Ca2+-activated channels had a mean single-channel conductance of ∼ 70 pS and showed a very fast activation. Both the single-channel open probability and the speed of activation increased with depolarization. Both parameters also increased in inside-out patches, i.e., in high Ca2+concentration. Intracellular loading with the Ca2+ chelator bis(2-aminophenoxy) ethane- N, N,N′,N′-tetraacetic acid gradually reduced and eventually prevented channel openings. The channels opened at very brief delays after the pulse depolarization onset (<5 ms), and the time-dependent open probability was constant during sustained depolarization (≤560 ms), matching both the extremely fast activation kinetics and the persistent nature of the macroscopic I K(Ca). However, the intrinsic properties of these single channels do not account for the partial apparent inactivation of the macroscopic I K(Ca), which probably reflects temporal Ca2+ variations in the whole muscle fiber. We conclude that the channels mediating I K(Ca) in crayfish muscle are voltage- and Ca2+-gated BK channels with relatively small conductance. The intrinsic properties of these channels allow them to act as precise Ca2+ sensors that supply the exact feedback current needed to control the graded electrical activity and therefore the contraction of opener muscle fibers.

scholarly journals Effects of Caffeine on Crayfish Muscle Fibers

1970 ◽  
Vol 55 (5) ◽  
pp. 665-687 ◽  
Author(s):  
Dante J. Chiarandini ◽  
John P. Reuben ◽  
Lucien Girardier ◽  
George M. Katz ◽  
Harry Grundfest
Keyword(s):  
Muscle Fibers ◽  
Bathing Medium ◽  
Contractile Responses ◽  
Crayfish Muscle ◽  
Contractile System ◽  
Mn Recovery

When caffeine evokes a contraction, and only then, crayfish muscle fibers become refractory to a second challenge with caffeine for up to 20 min in the standard saline (5 mM Ko). However, the fibers still respond with contraction to an increase in Ko, though with diminished tension. Addition of Mn slows recovery, but the latter is greatly accelerated during exposure of the fiber to high Ko, or after a brief challenge with high Ko. Neither the depolarization induced by the K, nor the repolarization after its removal accounts for the acceleration, which occurs only if the challenge with K had itself activated the contractile system; acceleration is blocked when contractile responses to K are blocked by reducing the Ca in the bath or by adding Mn. Recovery is accelerated by redistribution of intracellular Cl and by trains of intracellularly applied depolarizing pulses, but not by hyperpolarization. The findings indicate that two sources of Ca can be mobilized to activate the contractile system. Caffeine mobilizes principally the Ca store of the SR. Depolarizations that are induced by high Ko, by transient efflux of Cl, or by intracellularly applied currents mobilize another source of Ca which is strongly dependent upon the entry of Ca from the bathing medium. The sequestering mechanism of the SR apparently can utilize this second source of Ca to replenish its own store so as to accelerate recovery of responsiveness to a new challenge with caffeine.

scholarly journals Dual effect of L-glutamate on excitatory postjunctional membranes of crayfish muscle.

1975 ◽  
Vol 65 (5) ◽  
pp. 677-691 ◽  
Author(s):  
P S Taraskevich
Keyword(s):  
Muscle Fibers ◽  
Reversal Potential ◽  
Dual Effect ◽  
Sodium Conductance ◽  
Crayfish Muscle ◽  
Permeability Changes ◽  
Extracellular Sodium ◽  
Sodium And Potassium

Iontophoretically applied glutamate produces different excitatory postjunctional permeability changes on separate muscle fibers in a single crayfish muslce. At junctions on some fibers glutamate appears to increase the conductance to both sodium and potassium whereas at others its effect is primarily on the sodium conductance. These results obtained by studying the reversal potential for the extracellularly recorded glutamate potential under conditions of varied extracellular sodium and potassium concentrations.

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