1
|
Abstract
1. The intracellular Cl(-) concentration (Cl(i)) and the membrane potential (E(m)) were measured in the medial pleural neurones of Aplysia under various experimental conditions designed to determine the Cl(-) conductance of the neurones and investigate the possibility of an active Cl(-) transport.2. The magnitude of the Cl(-) conductance of the cell depends on the experimental conditions.3. In normal sea water, large changes of E(m) produced by passing current across the cell membrane caused no change of Cl(i), suggesting that the Cl(-) conductance was low. Similarly, moderate changes of E(Cl) produced by decreasing Cl(o) or increasing Cl(i) had little or no effect on E(m).4. A high Cl(-) conductance was observed in high K(o) or very low Cl(o). It was greatly reduced if the external Ca(2+) was replaced by Co(2+), or in the presence of tubocurarine, or if the experiment was performed on an isolated cell soma. The high Cl(-) conductance is therefore attributed to the release of ACh and perhaps other transmitters from synaptic terminals.5. High concentrations of tetraethylammonium ions or procaine induced a depolarization of the cell, but a decrease of Cl(i). The rate of fall of Cl(i) was increased by lowering external K(+) or raising external Ca(2+), and was decreased by replacing external Ca(2+) by Co(2+).6. NH(4) (+) ions applied externally had effects similar to those of K(+) ions. In situations in which intracellular NH(4) (+) might be increased a fall in Cl(i) was observed.7. The changes of Cl(i) caused by TEA, procaine, or internal NH(4) (+) occur against the driving force for passive Cl(-) movements. They are still observed in isolated cell bodies, and cannot be attributed to the activation of synaptic channels.8. Some interpretations of these anomalous Cl(-) movements are discussed which could also account for the difference between E(Cl) and E(m) observed under normal conditions.
Collapse
Affiliation(s)
- P Ascher
- Laboratoire de Neurobiologie, Ecole Normale Supérieure, 46, rue d'Ulm, Paris 75005, France
| | | | | |
Collapse
|
2
|
Yamagishi S, Grundfest H. Contributions of various ions to the resting and action potentials of crayfish medial giant axons. J Membr Biol 2013; 5:345-65. [PMID: 24173164 DOI: 10.1007/bf01957351] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/1971] [Indexed: 11/28/2022]
Abstract
The membrane of crayfish medial giant axons is permeable at rest to ions in the rank K>Na>Ca>Cl. With K present, variation of the other ions has little or no effect, but with K absent the axon hyperpolarizes when Na is reduced or eliminated by replacement with Tris (slope ca. 30 mV/decade Na0). The hyperpolarization is independent of the presence of Cl or its absence (substitution with methanesulfonate or isethionate). The resistance increases progressively as Na is removed. These changes persist after the spike is blocked with tetrodotoxin. An increase in Ca causes depolarization (slope ca. 20 mV/decade) provided K, Na and Cl are all absent, but in the presence of Cl there is little or no change in membrane potential on increasing Ca to 150MM. The depolarization induced by Ca is associated with an increased resistance. Spike electrogenesis involves Ca activation as well as Na activation, but the after-depolarization at the end of the spike is due to a conductance increase for Ca. Two alternative equivalent circuits for the resting and active membrane are discussed.
Collapse
Affiliation(s)
- S Yamagishi
- Laboratory of Neurophysiology, Department of Neurology, College of Physicians and Surgeons, Columbia University, 10032, New York, New York
| | | |
Collapse
|
3
|
|
4
|
Takeuchi A, Takeuchi N. On the permeability of the presynaptic terminal of the crayfish neuromuscular junction during synaptic inhibition and the action of gamma-aminobutyric acid. J Physiol 2010; 183:433-49. [PMID: 16992221 PMCID: PMC1357587 DOI: 10.1113/jphysiol.1966.sp007875] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. The contribution of chloride to presynaptic inhibition of the crayfish neuromuscular junction during the action of gamma-aminobutyric acid (GABA) and the inhibitory transmitter was investigated. Chloride in van Harreveld's solution was replaced with propionate, acetate, methylsulphate or glycerophosphate and electrical changes were recorded intracellularly and extracellularly with micro-electrodes.2. When the preparation was soaked in Cl-deficient solutions, the quantum content of the excitatory junctional potentials (e.j.p.s), calculated from the number of failures, was increased.3. The presynaptic inhibitory action of GABA was reduced or almost absent when the preparation was soaked in Cl-deficient solution. In Cl-deficient solution the stimulation of the inhibitory axon showed little or no inhibitory action on e.j.p.s.4. If GABA was applied shortly after the outside solution was changed to the Cl-deficient one, the frequency of the spontaneous e.j.p.s was increased transiently.5. It is suggested that GABA or the inhibitory transmitter act on the presynaptic excitatory terminal and predominantly increase its permeability to chloride.
Collapse
|
5
|
Sugi H, Ochi R. The mode of transverse spread of contraction initiated by local activation in single crayfish muscle fibers. ACTA ACUST UNITED AC 2010; 50:2145-66. [PMID: 19873574 PMCID: PMC2225776 DOI: 10.1085/jgp.50.9.2145] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Isolated single crayfish muscle fibers were locally activated by applying negative current pulses to a pipette whose tip was in contact with the fiber surface. The contraction initiated by a moderate depolarization spread inwards in a graded manner according to the magnitude and duration of depolarization. Increase of the depolarized area increased the distance of the inward spread for a given amount of depolarization. If a large area of the surface membrane was depolarized with a large pipette for a sufficiently long time, the contraction spread not only inwards, but further transversely passing through the center of the fiber. Successive brief depolarizations given at an appropriate interval could produce contraction more effectively for a given amount of total current than did a prolonged depolarization. On the other hand, the contraction initiated by a strong negative current was observed to spread around the whole perimeter but not through the center of the fiber. Each type of local contraction always spread along the striation pattern and not longitudinally. Possible mechanisms of these responses are discussed in connection with the transverse tubular system of the muscle fibers.
Collapse
Affiliation(s)
- H Sugi
- Department of Physiology, Faculty of Medicine, University of Tokyo, Tokyo, Japan
| | | |
Collapse
|
6
|
Krolenko SA, Lucy JA. Reversible vacuolation of T-tubules in skeletal muscle: mechanisms and implications for cell biology. INTERNATIONAL REVIEW OF CYTOLOGY 2001; 202:243-98. [PMID: 11061566 DOI: 10.1016/s0074-7696(01)02006-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
The majority of investigations of the transverse tubules (T-system) of skeletal muscle have been devoted to their role in excitation-contraction coupling, with particular reference to contact with the sarcoplasmic reticulum and the mechanism of Ca2- release. By contrast, this review is concerned with structural and functional aspects of the vacuolation of T-tubules. It covers experimental procedures used in reversible vacuolation induced by the efflux-influx of glycerol and other small nonelectrolytes, sugars, and ions. The characteristics of the phenomenon, associated alterations in muscle function, and the swelling of analogous structures in nonmuscle cells are considered. Possible functions of reversible vacuolation in water balance, transport, membrane repair, muscle pathology, and fatigue are considered, and the potential application of reversible vacuolation in the transfection of skeletal muscle is discussed. In relation to the possible mechanisms involved in reversible vacuolation, particular attention is given to the dynamic and structural aspects of the opening and closing of T-tubules, the origin of vacuolar membranes, and the localized character of tubular swelling.
Collapse
Affiliation(s)
- S A Krolenko
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg
| | | |
Collapse
|
7
|
REUBEN JP, GIRARDIER L, GRUNDFEST H. WATER TRANSFER AND CELL STRUCTURE IN ISOLATED CRAYFISH MUSCLE FIBERS. ACTA ACUST UNITED AC 1996; 47:1141-74. [PMID: 14192551 PMCID: PMC2195384 DOI: 10.1085/jgp.47.6.1141] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
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.
Collapse
|
8
|
Abstract
Localizations of aldehyde-resistant nucleoside phosphatase activities in frozen sections of rat cardiac muscle have been studied by electron microscopy. Activities are higher after fixation with formaldehyde than with glutaraldehyde. After incubation with adenosine triphosphate or inosine diphosphate at pH 7.2, reaction product is found in the "terminal cisternae" or "transverse sacs" of the sarcoplasmic reticulum, which, together with the "intermediary vesicles" (T system), constitute the "dyads" or "triads". Reaction product is also present at the membranes of micropinocytotic vacuoles which apparently form from the plasma membrane of capillary endothelial cells and from the sarcolemma. In certain regions of the intercalated discs, reaction product is found within the narrow spaces between sarcolemmas of adjacent cells and within micropinocytotic vacuoles that seem to form from the sarcolemma. With inosine diphosphate, reaction product is also found in other parts of the sarcoplasmic reticulum. After incubation with cytidine monophosphate at pH 5, reaction product is present in the transverse sacs of sarcoplasmic reticulum, in micropinocytotic vacuoles in capillary endothelium, and in lysosomes of muscle fibers and capillaries. The possible significance of the sarcoplasmic reticulum phosphatases is discussed in relation to the role the reticulum probably plays in moving calcium ions and thereby controlling contraction and relaxation of the muscle fiber.
Collapse
|
9
|
FRANZINI-ARMSTRONG C, PORTER KR. SARCOLEMMAL INVAGINATIONS CONSTITUTING THE T SYSTEM IN FISH MUSCLE FIBERS. ACTA ACUST UNITED AC 1996; 22:675-96. [PMID: 14208357 PMCID: PMC2106473 DOI: 10.1083/jcb.22.3.675] [Citation(s) in RCA: 254] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Striated muscle fibers from the body and tail myotomes of a fish, the black Mollie, have been examined with particular attention to the sarcoplasmic reticulum (SR) and transverse tubular (or T) system. The material was fixed in osmium tetroxide and in glutaraldehyde, and the images provided by the two kinds of fixatives were compared. Glutaraldehyde fixes a fine structure that is broadly comparable with that preserved by osmium tetroxide alone but differs in some significant details. Especially significant improvements were obtained in the preservation of the T system, that is, the system of small tubules that pervades the fiber at every Z line or A-I junction level. As a result of this improved glutaraldehyde fixation, the T system is now clearly defined as an entity of fine structure distinct from the SR but uniquely associated with the SR and myofibrils. Glutaraldehyde fixation also reveals that the T system is a sarcolemmal derivative that retains its continuity with the sarcolemma and limits a space that is in direct communication with the extracellular environment. These structural features favor the conclusion that the T system plays a prominent role in the fast intracellular conduction of the excitatory impulse. The preservation of other elements of muscle fine structure, including the myofibrils, seems for reasons discussed, to be substantially improved by glutaraldehyde.
Collapse
|
10
|
FREYGANG WH, GOLDSTEIN DA, HELLAM DC, PEACHEY LD. THE RELATION BETWEEN THE LATE AFTER-POTENTIAL AND THE SIZE OF THE TRANSVERSE TUBULAR SYSTEM OF FROG MUSCLE. ACTA ACUST UNITED AC 1996; 48:235-63. [PMID: 14225256 PMCID: PMC2195410 DOI: 10.1085/jgp.48.2.235] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This is an investigation of the effects on the late after-potential of immersing frog sartorius muscles in three kinds of modified Ringer's fluid; hypertonic, low chloride, and potassium-free. The late after-potential has been attributed to the depolarizing effect of an accumulation of potassium, during a preceding train of impulses, in the intermediary space of the model of a muscle fiber proposed by Adrian and Freygang. Both the hypertonic and low chloride solutions prolonged the late after-potential reversibly and the potassium-free solution shortened it. The effect of the low potassium solution fitted those data calculated from the model, but the effect of the hypertonic and low chloride solutions required an increase in size of the intermediary space of the model in order to fit the calculated data. An electron microscopic study of the muscles showed that the size of the transverse tubular system changed reversibly in the hypertonic and low chloride solutions in almost the amount necessary to fit the experimental data to the calculated data. This agreement between the change in size of the transverse tubular system and that of the intermediary space indicates that the intermediary space may be the transverse tubular system.
Collapse
|
11
|
ATWOOD HL, RAJ BS. TENSION DEVELOPMENT AND MEMBRANE RESPONSES IN PHASIC AND TONIC MUSCLE FIBERS OF A CRAB. ACTA ACUST UNITED AC 1996; 64:55-72. [PMID: 14200352 DOI: 10.1002/jcp.1030640107] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
12
|
GOLDMAN L. THE EFFECTS OF STRETCH ON CABLE AND SPIKE PARAMETERS OF SINGLE NERVE FIBRES; SOME IMPLICATIONS FOR THE THEORY OF IMPULSE PROPAGATION. J Physiol 1996; 175:425-44. [PMID: 14241841 PMCID: PMC1357145 DOI: 10.1113/jphysiol.1964.sp007525] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
|
13
|
GAINER H, KUSANO K, MATHEWSON RF. ELECTROPHYSIOLOGICAL AND MECHANICAL PROPERTIES OF SQUIRRELFISH SOUND-PRODUCING MUSCLE. ACTA ACUST UNITED AC 1996; 14:661-71. [PMID: 14327578 DOI: 10.1016/0010-406x(65)90253-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
14
|
Kaila K, Voipio J. Dependence of intracellular free calcium and tension on membrane potential and intracellular pH in single crayfish muscle fibres. Pflugers Arch 1990; 416:501-11. [PMID: 2235293 DOI: 10.1007/bf00382682] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The dependence of intracellular free calcium ([Ca2+]i) and tension on membrane potential and intracellular pH (pHi) was studied in single isolated fibres of the crayfish claw-opener muscle using ion-selective microelectrodes. Tension (T) was quantified as a percentage of the maximum force, or as force per cross-sectional area (N/cm2). In resting fibres, pHi had a mean value of 7.06. Contractions evoked by an increase extracellular potassium [( K+]0) produced a fall in pHi of 0.01-0.05 units. The lowest measured levels of resting [Ca2+]i corresponded to a pCai (= -log [Ca2+]i) of 6.8. Intracellular Ca2+ transients recorded during K(+)-induced contractions did not reveal any distinct threshold for force development. Both the resting [Ca2+]i and resting tension were decreased by an intracellular alkalosis and increased by an acidosis. The sensitivity of resting tension to a change in pHi (quantified as -dT/dpHi) showed a progressive increase during a fall in pHi within the range examined (pHi 6.2-7.5). The pHi/[Ca2+]i and pHi/tension relationships were monotonic throughout the multiphasic pHi change caused by NH4Cl. A fall of 0.5-0.6 units in pHi did not produce a detectable shift in the pCai/tension relationship at low levels of force development. The results indicate that resting [Ca2+]i is slightly higher than the level required for contractile activation. They also show that the dependence of tension on pHi in crayfish muscle fibres is attributable to a direct H+ and Ca2+ interaction at the level of Ca2+ sequestration and/or transport. Finally, the results suggest that in situ, the effect of pH on the Ca2+ sensitivity of the myofibrillar system is not as large as could be expected on the basis of previous work on skinned crustacean muscle fibres.
Collapse
Affiliation(s)
- K Kaila
- Department of Zoology, University of Helsinki, Finland
| | | |
Collapse
|
15
|
Salzberg BM, Obaid AL, Gainer H. Large and rapid changes in light scattering accompany secretion by nerve terminals in the mammalian neurohypophysis. J Gen Physiol 1985; 86:395-411. [PMID: 2997364 PMCID: PMC2228802 DOI: 10.1085/jgp.86.3.395] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Large changes in the opacity of the unstained mouse neurohypophysis follow membrane potential changes known to trigger the release of peptide hormones. These intrinsic optical signals, arising in neurosecretory terminals, reflect variations in light scattering and depend upon both the frequency of stimulation and [Ca2+]o. Their magnitude is decreased in the presence of Ca2+ antagonists and by the replacement of H2O in the medium by D2O. These observations suggest a correspondence between the intrinsic optical changes and secretory activity in these nerve terminals.
Collapse
|
16
|
Caillé J, Ildefonse M, Rougier O. Excitation-contraction coupling in skeletal muscle. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1985; 46:185-239. [PMID: 2418459 DOI: 10.1016/0079-6107(85)90009-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
17
|
Aldoroty RA, April EW. Donnan potentials from striated muscle liquid crystals. A-band and I-band measurements. Biophys J 1984; 46:769-79. [PMID: 6518255 PMCID: PMC1435105 DOI: 10.1016/s0006-3495(84)84075-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
A-band and I-band potentials are measured selectively in crayfish skinned long-tonic muscle fibers. The microelectrode tip diameters used in this study are shown to be sufficiently small to permit the discrete placement of an electrode into either an A-band or I-band. Random and directed impalements into mechanically skinned fibers with microelectrodes yields reproducible trimodal distributions of potentials where the modalities represent the A-band (-1.80 mV), the I-band (-0.76 mV), and the Z-line vicinity (-3.63 mV). In conjunction with Donnan equilibrium theory, fixed charge concentrations are calculated from the measured potentials for the A-band (25.9 mmol e-/l), I-band (10.9 mmol e-/l), and Z-line vicinity (52.3 mmol e-/l). When skinned fibers are treated with Triton X-100, the mean potentials (and charge concentrations) decrease: A-band to -1.71 mV (24.6 mmol e-/l), I-band to -0.71 mV (10.2 mmol e-/l), and the Z-line vicinity to -3.40 mV (49.0 mmol e/l). In the A-band this represents a loss of 1.3 mmol e-/l while in the I-band 0.7 mmol e-/l are lost; both decreases are attributed to the removal of internal membranous structures. In the rigor condition the A-band increases to -2.18 mV (33.1 mmol e-/l) and the I-band increases to -0.88 mV (13.3 mmol e-/l). Relative to the relaxed condition, this represents an increase of 8.5 mmol e-/l and 3.1 mmol e-/l in the A-band and I-band, respectively. The evidence shows that it is practical to measure A-band and I-band potentials selectively. Further, it is demonstrated that similar measurements can be obtained from agar, another polyelectrolyte gel system (see Appendix).
Collapse
|
18
|
Lnenicka GA, Mellon D. Changes in electrical properties and quantal current during growth of identified muscle fibres in the crayfish. J Physiol 1983; 345:261-84. [PMID: 6663501 PMCID: PMC1193796 DOI: 10.1113/jphysiol.1983.sp014977] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The muscle fibre electrical properties, miniature excitatory junctional current (m.e.j.c.) and miniature excitatory junctional potential (m.e.j.p.) were studied during growth of an identified crayfish muscle fibre from a diameter of 20 to 400 microns. The specific membrane resistance (Rm), and the specific internal resistance (Ri), of the muscle fibre were independent of fibre diameter (d) during growth. The current-voltage relation has a similar shape in large and small fibres, indicating that voltage dependence of Rm does not change during growth. The input resistance (R0) was approximately proportional to d-1.5, as predicted theoretically. The specific membrane capacitance (Cm) and the membrane time constant (Tm) increased linearly with fibre diameter, apparently as a result of the contribution of the tubular capacitance to Cm. The decrease in R0 and the increase in Tm should have resulted in a 90-fold decrease in m.e.j.p. amplitude during growth of the fibre from a diameter of 20 to 240 microns. However, m.e.j.p. amplitude was found to decrease only 21-fold. This discrepancy was shown to result from an increase in m.e.j.c. amplitude and duration during growth. There was 2.9-fold increase in m.e.j.c. amplitude and a 2.7-fold increase in m.e.j.c. duration over the range of muscle fibre growth studied. This increase in the m.e.j.c. apparently results from an increase in the magnitude and duration of the synaptic conductance change produced by a quantum of transmitter. Throughout the range of muscle fibre diameters studied, the muscle fibre effective input impedance for the m.e.j.c. was 17-19% of R0. This is due to the relatively large Cm and the short duration of the m.e.j.c.
Collapse
|
19
|
White RL. Effects of Acute Temperature Change and Acclimation Temperature on Neuromuscular Function and Lethality in Crayfish. ACTA ACUST UNITED AC 1983. [DOI: 10.1086/physzool.56.2.30156050] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
|
20
|
Reuben JP, Katz GM, Brandt PW, Suarez-Kurtz G, Dekin MS. Excitation-contraction coupling: role of K-activation within the transverse tubular system. Proc Natl Acad Sci U S A 1983; 80:988-92. [PMID: 6302678 PMCID: PMC393513 DOI: 10.1073/pnas.80.4.988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Long-duration Ca action potentials induced in crustacean muscle fibers after prolonged exposure to quaternary ammonium ions are accompanied by attenuated tensions with unique time courses. The tensions have three phases. The initial phase, correlated with the upstroke of the spike, is a rapid increase in tension followed by relaxation to or near to resting level (on-tension). In the second phase, tension rises slowly as the spike plateau declines. The final phase is another rapid increase and decay in tension that is correlated with termination of the action potential (off-tension). To observe these tensions, fibers must be exposed to 50-100 mM tetrabutylammonium ion for about 1 hr or to lower concentrations for longer periods (e.g., 5 mM for 20-30 hr). To obtain a similar response in fibers treated with tetraethylammonium ion, higher concentrations or longer soaking periods, or both, are required. Because neither caffeine-induced tensions in intact fibers nor contractile protein and sarcoplasmic reticulum function in skinned fibers were modified by quaternary ammonium ions, their site of action appears to be limited to surface or transverse tubular system membranes, or both. The unique tensions can be explained by considering the mode by which quaternary ammonium ions block K channels in conjunction with a scheme in which activation of K channels within the transverse tubular system controls the driving force for influx of Ca ions.
Collapse
|
21
|
Brûlé G, Haudecoeur G. [The effect of tetraethylammonium and the decrease in the extracellular chloride concentration on membrane depolarization and contraction of skeletal muscle fiber induced by a hyperpotassium solution]. ARCHIVES INTERNATIONALES DE PHYSIOLOGIE ET DE BIOCHIMIE 1982; 90:145-58. [PMID: 6186212 DOI: 10.3109/13813458209070565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
1.--The tetraethylammonium (TEA) effects on K+ contracture and membrane depolarization are compared in both crab and frog skeletal muscle fibres. 2.--The mechanical tension of the contracture is reduced by the TEA in frog skeletal muscle fibre; it is increased in crab skeletal fibre. 3.--When no mechanical phenomenon is observed in frog skeletal muscle, the amplitude and the velocity of membrane depolarization induced by an increase of outward K+ concentration is reduced by the TEA. These effects are in opposition in crab muscle fibre. 4.--In crab muscle fibre, the results obtained tend to show that the C1-ions are not distributed on each side of the membrane according to Donnan equilibrium.
Collapse
|
22
|
Kawai M, Brandt PW. Sinusoidal analysis: a high resolution method for correlating biochemical reactions with physiological processes in activated skeletal muscles of rabbit, frog and crayfish. J Muscle Res Cell Motil 1980; 1:279-303. [PMID: 6971874 DOI: 10.1007/bf00711932] [Citation(s) in RCA: 262] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
A high resolution method for determining the complex stiffness of single muscle fibres is described. In this method the length of the fibre is oscillated sinusoidally, and the resulting force amplitude and phase shift are observed and interpreted in terms of chemo-mechanical energy transduction. In activated, fast skeletal muscles of rabbit (psoas), frog (semitendinosus) and crayfish (walking leg flexor), we resolved at least three exponential rate processes. We named these (A), (B), (C) in order of slow to fast. These processes should reflect ATP hydrolysis and concomitant energy transduction since they are absent in muscles that the relaxed, in rigor or fixed. The great similarities in the complex stiffness data from different muscles suggests that there is a common mechanism of chemo-mechanical energy transduction across a broad phylogenetic range.
Collapse
|
23
|
Katz GM, Mozo A, Reuben JP. Filament interaction in intact muscle fibers monitored by light scattering. Proc Natl Acad Sci U S A 1979; 76:4421-4. [PMID: 291974 PMCID: PMC411587 DOI: 10.1073/pnas.76.9.4421] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Measurement of changes in optical properties of intact muscle fibers during contraction has proven to be difficult or, in some cases, impossible due to movement of the muscle relative to the incident beam. In this paper we describe a technique for immobilizing single fibers in clear gelatin, which permits measurement of light scattering signals undistorted by movement artifacts. We also describe the phase and amplitude relationship between changes in intensity of light scattering (at 90 degrees to incident beam) and tensions induced by electrically activating single fibers. With tensions that range up to 50% Po (Po = maximal tension measured by exposure of fibers to 200 mM K+), the maximal increase in light scattering is about 25% of that for resting fibers. The scattering increase precedes tension, and at low temperatures the interval between the two peaks can be 50--100 msec. We interpret these data on intact fibers, as we did our earlier data from studied on skinned fibers, as indicating that increases in light scattering power of muscle are primarily due to attachment of myosin cross-bridges to actin filaments.
Collapse
|
24
|
Mounier Y. Inactivation of the slow potassium outward current in crab muscle fibre. ARCHIVES INTERNATIONALES DE PHYSIOLOGIE ET DE BIOCHIMIE 1979; 87:501-8. [PMID: 93440 DOI: 10.3109/13813457909070514] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The slow outward current (IK2) recorded in crab muscle fibre using the double sucrose gap method decreases when high and maintained depolarizations are applied. This decrease corresponds to a true inactivation of the potassium conductance rather than to a shift in the reversal potential of the charge carrying ion following local accumulation.
Collapse
|
25
|
Suarez-Kurtz G, Sorenson AL. Dissociation of action potentials from contraction in single crab muscle fibers. Proc Natl Acad Sci U S A 1979; 76:3029-30. [PMID: 288085 PMCID: PMC383745 DOI: 10.1073/pnas.76.6.3029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In single crab fibers (Callinectes danae) bathed in Ca2+-free media, Ba2+ action potentials did not elicit tension. In contrast, Sr2+ spikes evoked twitches similar in amplitude to those accompanying the control Ca2+ spikes. Tension development in these fibers, therefore, depends on the ionic species carrying the inward current during membrane excitation. The Ca2" or Sr2+ influx appears insufficient to evoke the observed twitch tensions, and it seems necessary to postulate mobilization of an intracellular source of Ca1+. Procaine, which suppresses release of Ca2+ from sarcoplasmic reticulum, depressed twitch tension but did not reduce the overshoot or duration of Ca2+ or Sr2+ spikes. This finding is compatible with the suggestion that the contractions results from release of Ca2+ from the sarcoplasmic reticulum initiated by signals given by the influx of Ca2+ or Sr2+, but not Ba2+.
Collapse
|
26
|
Onodera K, Takeuchi A. An analysis of the inhibitory post-synaptic current in the voltage-clamped crayfish muscle. J Physiol 1979; 286:265-82. [PMID: 35608 PMCID: PMC1281570 DOI: 10.1113/jphysiol.1979.sp012618] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
1. Inhibitory post-synaptic currents (i.p.c.s) were recorded from the feed-back current through a wire electrode inserted longitudinally into the opener muscle fibre of the claw in the crayfish (Cambarus clarkii). 2. I.p.s.c. rose to its peak in about 3-4 msec and decayed approximately exponentially. The decay time constant at -100 mV was 9.4 msec. 3. The decay time constant decreased as the membrane was hyperpolarized and increased during depolarization. The time constant (tau) depends on voltage (V) according to the relation tau = a exp (AV), with a = 18.6 msec and A = 0.0065 mV-1. Voltage dependence was opposite in direction to that seen at frog end-plates, but in the same direction as that of e.p.s.c. in crayfish muscle. 4. At lower temperatures, the rise and fall times of i.p.s.c.s were prolonged. Q10 for the decay time constant was 2.4 between 22.6 and 12.5 degrees C. 5. When pH was decreased from 7.2 to 5.5, the decay time constant increased by about 50%, with little change in the voltage dependence of the time course. 6. When chloride in the solution was changed to iodide, the decay time constant was increased by a factor of 3, while voltage dependence of the time course was not changed. In bromide solution the decay time constant increased by about 50%. 7. Peak amplitudes of i.p.s.c.s were approximately linear as the membrane was depolarized, but they levelled off as the membrane was hyperpolarized beyond reversal potential. The non-linear I-V relation did not result from inadequate voltage clamping, nor from a change in the inside concentration of chloride. After equilibration with iodide solution the I-V relation was approximately linear. 8. The decay time constant was increased after repetitive nerve stimulation. This prolongation became more pronounced at lower temperatures. 9. The kinetic process of the transmitter action is discussed. It is suggested that the rate limiting process for i.p.s.c. is binding and unbinding of the transmitter to the receptor.
Collapse
|
27
|
Abstract
The proximal accessory flexor (PAF) of the myochordotonal organ (MCO) in the meropodite of crayfish walking legs contains two populations of muscle fibers which are distinguishable by their diameters. The large accessory (LA) fibers are 40-80 micrometer in diam and are similar in ultrastructure to other slow crustacean fibers. The small accessory (SA) fibers are 1-12 micrometer in diam and have a unique myofilament distribution at normal body lengths. There is extensive double overlap of thin filaments at these lengths, and some of them form bundles that may extend the length of the sarcomere. In the middle of the sarcomeres, thick and thin filaments are totally segregated from each other. When the fibers are stretched to lengths beyond double overlap length, the myofilament patterns are conventional. The segregated pattern is reestablished when stretched fibers are allowed to shorten passively. The length-tension relationship of the SA fibers is described by a linear ascending branch, a plateau, and a linear descending branch. The ascending branch encompasses normal body lengths from slack length (Ls) with maximum double overlap to the length at which double overlap ceases (1.8 X Ls). The descending phase is comparable to that of other skeletal muscles. That is, tension decreases in proportion with the reduction in thick-thin filament interdigitation (2 X Ls to 3 X Ls).
Collapse
|
28
|
Yamagishi S, Grundfest H. Regional differences in K channels of abdominal and circumesophageal segments of the crayfish medial giant axon. J Membr Biol 1977. [DOI: 10.1007/bf01869399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
29
|
Cohen LB, De Weer P. Structural and Metabolic Processes Directly Related to Action Potential Propagation. Compr Physiol 1977. [DOI: 10.1002/cphy.cp010105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
30
|
Dudel J. Voltage dependence of amplitude and time course of inhibitory synaptic current in crayfish muscle. Pflugers Arch 1977; 371:167-74. [PMID: 201918 DOI: 10.1007/bf00580786] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The membrane of small crayfish muscle fibers was clamped to potentials between-150 and -20 mV and amplitude and time course of inhibitory postsynaptic currents (IPSCs) were studied. The IPSCs were recorded extracellularly by means of a focal microelectrode and also as total clamp current. The IPSCs lasted about 40 ms and were slowed by depolarization. The rate constant alpha of decay of the IPSC depended on membrane potential E according to the relation alpha= 44 s-1 -e-8.7 V E at 13.5 degrees C. alpha increased with temperature with a Q10 of 1.9 to 2.5. The amplitude iI of the IPSC depended nonlinearly on E and decreased with time after a potential shift. This was partly due to movement of Cl--ions, the difference (E--EI) between clamp potential and reversal potential for the IPSC decreasing to a few mV within several minutes after a shift in E. The inhibitory conductance gI increased up to 30-fold for 100 mV depolarization also changed with time. However, the the inhibitory permeability PI proved to be independent of membrane potential and time. The potential dependence of gI is thus largely due to changes in the internal Cl--concentration.
Collapse
|
31
|
Kawai M, Brandt P, Orentlicher M. Dependence of energy transduction in intact skeletal muscles on the time in tension. Biophys J 1977; 18:161-72. [PMID: 140712 PMCID: PMC1473282 DOI: 10.1016/s0006-3495(77)85605-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In intact single crayfish muscle fibers and frog semitendinosus muscles we have studied the tension response to sinusoidal length changes in the frequency range of 0.25-133 Hz. By this method we have resolved three processes in the interaction of myosin cross-bridges with actin in fully activated preparations. They are (A) a low-frequency phase advance, (B) a middle-frequency delay, and (C) a high-frequency advance. These processes can be used as probes to study the chemomechanical coupling of contractility. Process (B) represents net power output from the muscle preparation (oscillatory work). With maximal K or caffeine activation of crayfish muscle at 20 degrees C, it decreases to zero in the initial 45 s of maintained tension. Similar results were obtained with frog semitendinosus whole muscles. We interpret this decrease of (B) with time as a gradual decrease in actomyosin ATP-hydrolysis rate.
Collapse
|
32
|
Onodera K, Takeuchi A. Permeability changes produced by L-glutamate at the excitatory post-synaptic membrane of the crayfish muscle. J Physiol 1976; 255:669-85. [PMID: 1263139 PMCID: PMC1309273 DOI: 10.1113/jphysiol.1976.sp011302] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
1. Permeability changes produced by L-glutamate at the neuromuscular junction of the crayfish (Cambarus clarkii) were investigated by application of the drug iontophoretically to the voltage-clamped junction and measuring the resulting 'glutamate current'. 2. Reversal potentials were determined by measuring the glutamate current at different membrane potentials. They were +39-1 +/- 3-6 mV (mean +/- S.E. of mean) in normal solution and +16-5 +/- 2-0 mV in solutions made twice as hypertonic by the addition of sucrose. 3. Decreasing external Na+ concentration shifted the reversal potential in the negative direction; increased Na+ in the positive direction. 4. The relation between the amplitude of the glutamate current and extracellular Na+ concentration was approximately linear. 5. Alteration of the external K+ or Cl- concentration did not affect the amplitude or reversal potential of glutamate current. 6. In Na+-free solution the application of L-glutamate produced a small inward current at the resting potential and its amplitude was augmented by increasing the external Ca2+ concentration. 7. Increasing the Ca2+ concentration in the normal Na+ media produced no appreciable effect on the reversal potential but decreased the amplitude of glutamate current. 8. The results indicate that L-glutamate increases the membrane permeability mainly to Na+ and slightly to Ca2+. 9. The time course of glutamate current was shorter than that of the concentration calculated from the diffusion equation and it was simulated more closely by the square of the concentration.
Collapse
|
33
|
Costantin LL. Contractile activation in skeletal muscle. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1976; 29:197-224. [PMID: 1094492 DOI: 10.1016/0079-6107(76)90023-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
34
|
Onodera K, Takeuchi A. Ionic mechanism of the excitatory synaptic membrane of the crayfish neuromuscular junction. J Physiol 1975; 252:295-318. [PMID: 1202198 PMCID: PMC1348479 DOI: 10.1113/jphysiol.1975.sp011145] [Citation(s) in RCA: 73] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
1. The reversal potential for the excitatory neuromuscular junction of the crayfish (Cambarus clarkii) was measured using the voltage clamp method. The potential change was recorded with an intracellular microcapillary and the negative phase of the output of the feed-back amplifier was connected to the stainless-steel wire which was inserted longitudinally into the muscle fibre. 2. When the excitatory nerve was stimulated, a transient feed-back current flowed inwardly through the membrane. This current was called the excitatory junctional current (e.j.c.). 3. Reversal potentials were determined by extrapolating the e.j.c.s measured at different membrane potentials. They were about 10-20 mV positive with respect to the bath solution (11-5 +/- 1-2 mV, mean +/- S.E.). 4. The reversal potential for the iontophoretically applied glutamate was identical with that for the e.j.c. 5. In hypertonic solutions, the reversal potentials for e.j.c. and glutamate became more negative. 6. When the sodium concentration of the bath solution was decreased, the reversal potential became more negative. 7. When the chloride and potassium concentration were altered, little, if any, change was observed in the reversal potential. 8. It was concluded that the e.j.c. was carried mainly by sodium ions. Contribution of other ions, possibly calcium ions, was discussed.
Collapse
|
35
|
Mounier Y, Vassort G. Initial and delayed membrane currents in crab muscle fibre under voltage-clamp conditions. J Physiol 1975; 251:589-608. [PMID: 1185676 PMCID: PMC1348405 DOI: 10.1113/jphysiol.1975.sp011110] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Membrane currents are investigated under voltage-clamp conditions in crab muscle fibre. 2. Step depolarizations elicit an initial composite current followed by a late outward current. 3. One of the components of the initial current is inward. It is sensitive to the external calcium concentration and inhibited by manganese ions, it can be carried also by strontium ions; thus it is expected to be a calcium current. 4. In TEA solution this calcium current appears alone, it reverses when the membrane polarization is carried beyond an internal potential of +30 or +35 mV. Such a low equilibrium potential for calcium ions can be explained either by a low selectivity of the calcium channel or by a local accumulation of calcium ions. 5. Calcium conductance shows voltage- and time dependence. 6. The late outward current corresponds to a potassium current and is inhibited by TEA ions. Its activation exhibits voltage- and time dependence. 7. The activation curve of the late potassium current is shifted in a depolarizing direction by addition of manganese ions. A similar shift produced by increasing [Ca]o or decreasing [Ca]i has been described on other preparations. It is then supposed that the electrical field of the membrane is modified by the gradient of double cations.
Collapse
|
36
|
Geiman HM, Rubinstein LI. Passive transfer of low-molecular nonelectropolytes across deformable semipermeable membranes. II. Dynamics of a single muscle fiber swelling and shrinking and related changes of the T-system tubule form. Bull Math Biol 1974; 36:379-401. [PMID: 4457190 DOI: 10.1007/bf02464616] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
37
|
Suarez-Kurtz G. Inhibition of membrane calcium activation by neomycin and streptomycin in crab muscle fibers. Pflugers Arch 1974; 349:337-49. [PMID: 4472151 DOI: 10.1007/bf00588419] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
38
|
Lea TJ, Usherwood PN. Effect of ibotenic acid on chloride permeability of insect muscle-fibres. COMPARATIVE AND GENERAL PHARMACOLOGY 1973; 4:351-63. [PMID: 4799404 DOI: 10.1016/0010-4035(73)90046-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
39
|
Hinkle M, Van der Kloot W. The effects of valinomycin on striated muscles of the frog and the crayfish. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. A, COMPARATIVE PHYSIOLOGY 1973; 46:269-78. [PMID: 4147895 DOI: 10.1016/0300-9629(73)90417-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
40
|
Abstract
1. Membrane constants of the closer muscle of the ghost crab, Ocypoda cursor, were determined before and after treatment in hypertonic glycerol solution and return to an artificial sea-water (A.S.W.) solution.2. Muscle contraction was abolished after return of the muscle to A.S.W.3. The membrane capacitance was reduced from 29.0 muF/cm(2) to 10.5 muF/cm(2).4. Other passive properties of the muscle membrane, not dependent on capacitance, were not changed.5. The presynaptic nerve, transmitter release, post-synaptic sensitivity to transmitter and ionic mechanisms of synaptic action were unaffected by glycerol treatment.6. More than 60% of the membrane capacitance/unit area is contributed by the complex tubular system.7. The tubular system in crustacea is necessary for excitation-contraction coupling.
Collapse
|
41
|
Cohen LB, Keynes RD, Landowne D. Changes in axon light scattering that accompany the action potential: current-dependent components. J Physiol 1972; 224:727-52. [PMID: 5071935 PMCID: PMC1331517 DOI: 10.1113/jphysiol.1972.sp009920] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
1. When light scattering was measured during hyperpolarizing and depolarizing voltage-clamp steps, relatively large scattering changes were found during the depolarizing steps. These large changes were found to depend on the time integral of the ionic current and not on the changes in conductance or potential.2. The current-dependent changes were examined at several scattering angles, and three distinct time courses were found. At 30-120 degrees , the main change occurred after the current when steps of 2-5 msec duration were used. This change was called I-90 degrees . At 15-30 degrees , the change occurred with the same time course as the time integral of the current. This change was called I-25 degrees . At 5-15 degrees the scattering change occurred with a time course intermediate between that of I-90 degrees and I-25 degrees . This change was called I-10 degrees .3. In all experiments, outward potassium and outward sodium currents led to similar light scattering changes indicating that specific effects of the cation carrying the current across the membrane were not involved.4. The size of I-90 degrees was reduced by 29% when an isethionate artificial sea water was substituted for the normal chloride artificial sea water. This reduction equalled the reduction predicted for a transport number effect at the membrane-solution interface. The time course of I-90 degrees was similar to the predicted time course for a volume change in the periaxonal space, and such volume changes were tentatively identified as the origin of I-90 degrees .5. Because of difficulties in measuring the time course of I-25 degrees , it was not possible to distinguish between a water of hydration effect and a transport number effect as the cause of this change. Similarly, the origins of I-10 degrees were not identified. Only I-10 degrees was altered in size and time course when the external refractive index was increased with bovine albumin.6. When the scattering changes during the action potential were examined in light of the voltage-clamp experiments, we concluded that the forward-angle change was potential-dependent and that the long-lasting change at right angles probably represented a swelling of the periaxonal space resulting from the fact that chloride carried a significant fraction of the outward current during the action potential.
Collapse
|
42
|
Suarez-Kurtz G, Reuben JP, Brandt PW, Grundfest H. Membrane calcium activation in excitation-contraction coupling. J Gen Physiol 1972; 59:676-88. [PMID: 5025745 PMCID: PMC2203197 DOI: 10.1085/jgp.59.6.676] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Depolarization thresholds for eliciting tension and Ca electrogenesis have been compared in isolated crayfish muscle fibers. Just-detectable tensions and Ca spikes induced after treatment with procaine were elicited with intracellularly applied depolarizing currents of fixed duration. Both thresholds were found to increase in a similar manner in fibers exposed to increased concentrations of Ca in the bathing solution or addition of other divalent cations (Mg, Mn, Ni). However, antagonistic effects between divalent cations were also demonstrated. Substitution of increasing amounts of NaSCN for NaCl in the standard saline produced a progressive decrease in both thresholds. The correlation in the change in thresholds for the two processes supports the hypothesis that a change in membrane Ca conductance is an integral step in excitation-contraction coupling.
Collapse
|
43
|
Kohn PG, Clausen T. The relationship between the transport of glucose and cations across cell membranes in isolated tissues. VII. The effects of extracellular Na + and K + on the transport of 3-O-methylglucose and glucose in rat soleus muscle. BIOCHIMICA ET BIOPHYSICA ACTA 1972; 255:798-814. [PMID: 5020225 DOI: 10.1016/0005-2736(72)90392-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
44
|
Hodgkin AL, Nakajima S. The effect of diameter on the electrical constants of frog skeletal muscle fibres. J Physiol 1972; 221:105-20. [PMID: 4536963 PMCID: PMC1331323 DOI: 10.1113/jphysiol.1972.sp009742] [Citation(s) in RCA: 168] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
1. Electrical constants were determined on isolated single fibres or on fibres from bundles from frog's twitch muscles by analysing the low frequency cable properties.2. The sarcoplasmic conductivity (G(i)) was 5.9 mmho/cm at 20 degrees C, and its temperature coefficient (Q(10)) was 1.37.3. The Q(10) of the membrane conductance (G(M)) was 1.49, and that of the membrane capacity (C(M)) was 1.02.4. C(M) increases with diameter (D) in an approximately linear manner: the values were 4.6 muF/cm(2) at D = 50 mu, and 8.5 muF/cm(2) at D = 130 mu.5. G(M) also increases with diameter, being 0.21 mmho/cm(2) at D = 50 mu and 0.37 mmho/cm(2) at D = 130 mu.6. These results suggest that the transverse tubular system contributes substantially to the values of low frequency capacity and conductance measured at the surface membrane.
Collapse
|
45
|
Katz GM, Reuben JP, MacBerman, Dunham PB. Potassium redistribution and water movement in crayfish muscle fibers. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 1972. [DOI: 10.1007/bf00694841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
46
|
Orentlicher M, Reuben JP. Localization of ionic conductances in crayfish muscle fibers. J Membr Biol 1971; 4:209-26. [DOI: 10.1007/bf02431972] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/1970] [Indexed: 10/24/2022]
|
47
|
April EW, Brandt PW, Elliott GF. The myofilament lattice: studies on isolated fibers. I. The constancy of the unit-cell volume with variation in sarcomere length in a lattice in which the thin-to-thick myofilament ratio is 6:1. J Cell Biol 1971; 51:72-82. [PMID: 5111882 PMCID: PMC2108234 DOI: 10.1083/jcb.51.1.72] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The spacing between the thick myofilaments of muscle fibers from the walking legs of crayfish (Orconectes) was determined by optical transform analysis of electron micrograph plates of fixed single fibers and by X-ray diffraction of living single fibers. Sarcomere lengths were determined by light diffraction prior to fixation and prior to the in vivo experiments. From these combined measurements, it is demonstrated that the unit-cell volume of the myofilament lattice is constant during muscle shortening, indicating that the myofilament lattice works in a constant-volume manner. It is further demonstrated with X-ray diffraction measurements of living single fibers that the myofilament lattice continues to work at constant volume after the sarcolemma is removed from the fiber. This indicates that the constant-volume behavior of muscle is inherent to the myofilament lattice.
Collapse
|
48
|
Hinkle M, Heller P, Van der Kloot W. The influence of potassium and chloride ions on the membrane potential of single muscle fibers of the crayfish. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. A, COMPARATIVE PHYSIOLOGY 1971; 40:181-201. [PMID: 4401094 DOI: 10.1016/0300-9629(71)90160-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
49
|
Law PK, Atwood HL. Membrane resistance change induced by nitrate and other anions in long and short sarcomere muscle fibres of crayfish. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. A, COMPARATIVE PHYSIOLOGY 1971; 40:265-71. [PMID: 4401100 DOI: 10.1016/0300-9629(71)90166-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
50
|
Abstract
This report deals with the diffusional and nondiffusional water fluxes of muscle fibers of the crab, Chionoecetes bairdi. Graphical analysis of the deuterium exchange indicates that two fiber compartments exist for water. The first, comprising about 60-70% of the fiber water, probably represents the sarcoplasm which is bounded externally by the plasma membrane. The second compartment might represent intracellular organelles. The ratio between the nondiffusional and diffusional fluxes is very much larger than that found earlier for erythrocytes and for the giant axon of the squid. A ratio of such size is unlikely to be caused by unstirred layers and more accurate determinations of the water flux must include study of the influence of the complex morphology of these muscle fibers.
Collapse
|