ATP Diffusion Research Articles

Intercellular Communication in Spinal Cord Astrocytes: Fine Tuning between Gap Junctions and P2 Nucleotide Receptors in Calcium Wave Propagation

Electrophysiological properties of gap junction channels and mechanisms involved in the propagation of intercellular calcium waves were studied in cultured spinal cord astrocytes from sibling wild-type (WT) and connexin43 (Cx43) knock-out (KO) mice. Comparison of the strength of coupling between pairs of WT and Cx43 KO spinal cord astrocytes indicates that two-thirds of total coupling is attributable to channels formed by Cx43, with other connexins contributing the remaining one-third of junctional conductance. Although such a difference in junctional conductance was expected to result in the reduced diffusion of signaling molecules through the Cx43 KO spinal cord syncytium, intercellular calcium waves were found to propagate with the same velocity and amplitude and to the same number of cells as between WT astrocytes. Measurements of calcium wave propagation in the presence of purinoceptor blockers indicate that calcium waves in Cx43 KO spinal cord astrocytes are mediated primarily by extracellular diffusion of ATP; measurements of responses to purinoceptor agonists revealed that the functional P2Y receptor subtype is shifted in the Cx43 KO astrocytes, with a markedly potentiated response to ATP and UTP. Thus, the reduction in gap junctional communication in Cx43 KO astrocytes leads to an increase in autocrine communication, which is a consequence of a functional switch in the P2Y nucleotide receptor subtype. Intercellular communication via calcium waves therefore is sustained in Cx43 null mice by a finely tuned interaction between gap junction-dependent and independent mechanisms.

ATP Transport Through a Single Mitochondrial Channel, VDAC, Studied by Current Fluctuation Analysis

The “molecular Coulter counter” concept has been used to study transport of ATP molecules through the nanometer-scale aqueous pore of the voltage-dependent mitochondrial ion channel, VDAC. We examine the ATP-induced current fluctuations and the change in average current through a single fully open channel reconstituted into a planar lipid bilayer. At high salt concentration (1M NaCl), the addition of ATP reduces both solution conductivity and channel conductance, but the effect on the channel is several times stronger and shows saturation behavior even at 50mM ATP concentration. These results and simple steric considerations indicate pronounced attraction of ATP molecules to VDAC’s aqueous pore and permit us to evaluate the effect of a single ATP molecule on channel conductance. ATP addition also generates an excess noise in the ionic current through the channel. Analysis of this excess noise shows that its spectrum is flat in the accessible frequency interval up to several kilohertz. ATP exchange between the pore and the bulk is fast enough not to display any dispersion at these frequencies. By relating the low-frequency spectral density of the noise to the equilibrium diffusion of ATP molecules in the aqueous pore, we calculate a diffusion coefficient D=(1.6–3.3)10−11 m2/s. This is one order of magnitude smaller than the ATP diffusion coefficient in the bulk, but it agrees with recent results on ATP flux measurements in multichannel membranes using the luciferin/luciferase method.

Role of the Golgi Apparatus in the Phosphorylation of Apolipoprotein B

Rat hepatic Golgi apparatus-rich fractions were utilized in an in vitro phosphorylation system containing [gamma-32P]ATP to investigate the phosphorylation of apolipoproteins (apo) B48 and B100. Our results demonstrate that the Golgi apparatus contains a kinase(s) that phosphorylates both apoB48 and apoB100 as well as 290- and 460-kDa proteins recognized by antibody to apoB. We refer to the latter proteins as apoB57 and apoB90, respectively. Phosphorylations in the presence of Triton X-100, which increases the permeability of the membranes, or alamethicin, an ionophore that facilitates transmembrane diffusion of ATP, indicate that the active site of the kinase is on the luminal side of the membranes. However, studies with EDTA and EGTA, which are inhibitory to the kinase, suggest binding sites for Mg2+ and perhaps Ca2+ on the cytosolic membrane face. Phosphorylation of apoB was not stimulated by cAMP nor inhibited by protein kinase inhibitor peptide (5-24), indicating that cAMP dependent protein kinase was not involved in the phosphorylation process. Sodium carbonate treatment of the phosphorylated fraction, which permits separation of membrane and luminal contents, revealed that phosphorylated apoB90 and apoB57 are associated primarily with the membrane, whereas phosphorylated apoB48 is found in luminal contents as well as with the membranes. Phosphorylated apoB100 was found primarily with the membrane fraction. No evidence was found for phosphorylation of apoB in rough endoplasmic reticulum fractions. These studies demonstrate the importance of the Golgi apparatus as a subcellular site for the phosphorylation of apoB and suggest that apoB phosphorylation may be important in the assembly and secretion of apoB-containing lipoproteins.

The importance of the creatine kinase reaction

The creatine kinase reaction is traditionally viewed as providing an energy reserve in muscle. However, the physiological importance of this reaction (and the analogous invertebrate reaction catalyzed by arginine kinase) is better understood when viewed as providing metabolic capacitance. This capacitance allows reduction of peak rates of ATP synthesis in cells that alternate between periods of high and low energy consumption. Furthermore, the capacitance allows repayment of energy "debt" that is incurred during periods of high energy demand to occur during periods of low rates of energy consumption. The creatine kinase reaction provides facilitated diffusion of ATP and ADP, which leads to spatial buffering in addition to temporal buffering. Data are presented which suggest that the existence of the creatine kinase reaction allows muscle cells to maintain reduced mitochondrial volume, support larger diameter fibers, and express faster isoforms of myosin. These data lead to speculation that there may be a coupling in the expression of metabolic and contractile proteins.

ATP dependence of KATP channel kinetics in isolated membrane patches from rat ventricle

The dependence of KATP channel activity on [ATP] has been examined in isolated membrane patches from rat ventricular myocytes. The steady-state [ATP] dependence of channel open probability could be described by a sigmoidal relationship with the ki ([ATP] causing half-maximal inhibition of open probability) = 25 microM and Hill coefficient of 2. Description of channel open- and closed-time distributions required at least 2, and 3, time constants, respectively. Long open-channel lifetimes decreased with [ATP]; unconditional mean channel closed-times increased with [ATP]. Step decrease (jump) in bathing [ATP] resulted in a delay (of up to hundreds of milliseconds) followed by a pseudo-exponential rise of current (with a time constant of up to hundreds of milliseconds). The time course of channel current after changes of [ATP] (or the ATP-analogue AMP-PNP) was shown to be predominantly determined by the time course of diffusion into the tip of the electrode and to the membrane. This time course of diffusion of ATP into the pipette tip had to be taken into account when analyzing the current response to [ATP] steps. Several possible kinetic models of the ATP-dependent regulation of channel activity were considered. Adequate explanation of the data required a model with sequential ATP-binding sites. The model can account for the time course of channel opening after steps of [ATP], as well as for the steady-state dependence of P0 on [ATP]. The model predicts [ATP]-dependent closed and open lifetimes as were observed experimentally.

Dose Effects of Cholecystokinin and Acetylcholine on Phosphorus Compounds and Secretory Responses in Isolated Perfused Pancreas of Rat.

Phosphorus nuclear magnetic resonance (31P NMR) spectroscopy was used to study energy supply for protein secretion in the isolated perfused rat pancreas. Stimulation with cholecystokinin (CCK-8) increased fluid secretion and protein output. With 10pM of CCK-8, the tissue contents of ATP, inorganic phosphate (Pi), and creatine phosphate (PCr) remained unchanged. With 100pM of CCK-8, which induced the maximum response in fluid secretion and protein output, Pi increased slightly, ATP and PCr remained almost unchanged. A high dose of CCK-8 (1 nM) suppressed the fluid and protein secretory rates, decreased ATP, and increased Pi significantly, but PCr showed a tendency of increase. Significant changes in ATP and Pi occurred on withdrawal of CCK-8 (1 nM), suggesting activation of ATP hydrolysis for recovery from secretory suppression. During stimulation with 0.1, 0.3, and 3.0 microM of acetylcholine, the similar dose-dependent response was observed in the secretion and the phosphorus metabolism. The present study demonstrated that cytosolic energy metabolism for secretory responses in the pancreas is low and the Lohmann reaction showed less contribution than in the salivary gland. The findings suggest that the energy supply for protein secretion may be cytosolic diffusion of ATP and that the Lohmann reaction system may contribute to synthesis and storing of secretory protein at resting state.

Diffusion-limited kinetics of immobilized myosin ATPase

To test the possibility that ATP diffusion limits the kinetics of myosin ATPase (EC.3.6.1.3) in situ, myosin was covalently bound to the surface of 2 kinds of films: collagen and Immunodyne™. On collagen films, it was bound either with 1-ethyl-3(3-dimethyl-aminopropyl)carbodiimide (EDC) or with dimethyl-3,3′-dithio bis(propionimidate) (DTP). The apparent K m for K −-ATP rose from 0.26 mM for free myosin in solution to 2–5 mM for covalently bound myosin, and maximum K −-ATPase activity was very low. With the other film, Immunodyne™ from Pall®, the maximum activity of bound myosin was 170 nmol per min per 1.5 cm 2 film. The apparent K m for K −-ATP was 2.1 mM when the incubation mixture was vigorously stirred, and the effect of stirring indicated that the kinetics of K −-ATP hydrolysis are limited by external diffusion. The large amount of myosin bound per unit of Immunodyne film surface permitted the study of Mg 2-ATPase activity, although it was 400–500 times less than the K −-ATPase activity. The apparently non-Michaelian kinetics of Mg 2-ATP hydrolysis are attributable to the external diffusion. The apparent Michaelis constant observed at low Mg 2−-ATP concentrations rose from 0.27 μM for myosin in solution to 5 μM for myosin bound to Immunodyne film.

Changes of membrane currents in cardiac cells induced by long whole-cell recordings and tolbutamide

Single isolated myocytes were obtained from the ventricles of adult guinea pig hearts. The whole-cell recording configuration of the patch-clamp technique was used to measure membrane currents. A decrease (run-down) of the Ca2+ inward current and an increase of a time-independent K+ outward current were observed during long lasting (1-3h) recordings. The time at which the outward current developed depended on the intracellular ATP concentration in the pipette, suggesting that this current is identical to the ATP-dependent K+ current described by Noma and Shibasaki (1985). However, the maximum outward current reached in the experiments was independent of the ATP concentration indicating a limited diffusion of ATP in the cell interior. In single-channel experiments on isolated patches of cell membrane and in whole-cell recordings the ATP-dependent K+ current could be blocked by the hypoglycaemic sulphonylurea tolbutamide. The IC50 of 0.38 mM was about 50 times higher than that reported for pancreatic beta-cells (Trube et al. 1986). The Ca2+ inward current and the inwardly rectifying K+ current were not affected by tolbutamide (3 mM).

Influence of Chlorpromazine on the Accumulation of 5-Hydroxytryptamine by Interaction with ATP

5-Hydroxytryptamine accumulates at pH 6.0 when ATP is present on one side of an artificial lipoidal barrier. In the presence of chlorpromazine, the diffusion of ATP through the barrier and a decrease in the accumulation of serotonin can be noted. The diffusion rate constants of ATP and serotonin are related to the concentration of chlorpromazine.

ATP concentration gradients in cytosol of liver cells during hypoxia.

The activities of two ATP-requiring systems with different subcellular localizations were studied in cells in which average cellular ATP concentration was varied. The cytosolic ATP-sulfurylase activity varied linearly with the cellular ATP concentration; however, the plasma membrane Na+-K+-ATPase was substantially more sensitive to decreased ATP concentration. Under conditions where the cellular ATP concentration was lowered to 40% of control, Rb+ uptake was nearly zero. The results indicate that ATP-utilizing enzymes located in the plasma membrane in liver cells are exposed to a lower ATP concentration than are enzymes present in the cytosolic fluid surrounding the mitochondria. Analysis of radial diffusion of ATP from mitochondria, assuming that mitochondria are spherical and ATP consumption is zero order in ATP concentration, shows that the average ATP supply radius decreases as mitochondrial ATP production decreases. Hence, during limited ATP supply, enzymes with a greater average distance from mitochondria (e.g., plasma membrane ATPases) experience a more dramatic decrease in ATP concentration than enzymes in close proximity to mitochondria (e.g., cytoplasmic enzymes). Thus microheterogeneity of ATP supply can occur in cells without membranal compartmentation due to nonuniform distribution of ATP-generating and ATP-consuming systems.

A model for intracellular energy transport.

A model for oxygen transfer to cells from capillaries is considered in which mitochondria are either clustered at the cell periphery around capillaries or homogeneously distributed through the cytosol. The capillary Po2 required to supply cells utilizing oxygen at the same rate is much less when mitochondria cluster around capillaries. Two alternative mechanisms are considered for distributing energy from peripheral mitochondria to the rest of the cell; i.e., diffusion of ATP or creatine phosphate with enough creatine kinase to ensure equilibrium between the approximately P carriers. The latter has clear advantages and would appear to be adequate to supply a fairly large mitochondria-free cell core (e.g., 24-micrometer diameter) with very little change in ADP levels or in the free energy of ATP hydrolysis at maximum work rates. Thus, a viable alternative to the traditional Krogh model is presented which takes into account the inhomogeneity of the diffusion pathway as a result of mitochondrial clustering.

A study of the distribution of mitochondria in some oxidative muscle fibres of the pig

Some muscle fibres in the longissimus dorsi muscle of the pig contain numerous longitudinally-orientated columns of mitochondria which seem non-randomly distributed. The nature of the distribution pattern has been analysed using a quantitative nearest neighbour technique. In this method the mean real distance between the mitochondrial columns is compared with the calculated mean theoretical distance between columns which would occur if they were assumed to be randomly distributed. It was found that the distribution pattern of mitochondrial columns results from hyperdispersion— i.e. they are more widely separated from each other than they would be if they were distributed randomly. It is suggested that the hyperdispersion of mitochondria is related to the activity of the fibres. It is possible that this type of mitochondrial distribution facilitates the efficient diffusion of ATP from the mitochondria to the myofibrils. Geometrical probability techniques in general might be useful in providing much data on the organization of cells and tissues.

Localized activation of bending in proximal, medial and distal regions of sea-urchin sperm flagella.

ABSTRACT Spermatozoa from the sea urchin, Colobocentrotus atratus, were partially demembranated by extraction with solutions containing Triton X-100 at a concentration which was insufficient to solubilize the membranes completely. The resulting suspension was a mixture containing some spermatozoa in which a proximal, medial, or distal portion of the flagellum was membrane covered, while the remaining portion was naked axoneme. In reactivating solutions containing 12 μ M ATP, only the naked portions of the flagellum became motile. In reactivating solutions containing 0·8 mM ADP, the membrane-covered regions became motile and beat at 6–10 beats/s, while the naked regions remained immobile, or beat very slowly at about 0·3 beat/s. Activation of membrane-covered regions in ADP solutions probably results from the membrane restricting the diffusion of ATP which is formed from ADP by the axonemal adenylate kinase. The results indicate that any region of the flagellum has the capacity for autonomous beating, and that special properties of the basal end of the flagellum are not required for bend initiation. How ever, the beating of different regions of the flagellum is not completely independent, for in a fair number of spermatozoa the beating of the distal, membrane-covered region in 0·8 mM ADP was intermittent, and was turned on and off in phase with the much slower bending cycle in the proximal region of naked axoneme.

Potentiation of contraction of glycerol-extracted muscle by deoxycholate.

SummaryTreatment with the detergent deoxycholate potentiates the rate and extent of the ATP-induced contraction of both thick (485 μ) glycerol-extracted arterial muscle and thick (700 μ) skeletal muscle fiber bundles. Deoxycholate does not affect the ATP-induced contraction of thin glycerol-extracted fiber bundles (180 and 135 μ for arterial muscle and skeletal muscle fiber bundles, respectively) . It does not affect the Ca-induced contraction of arterial muscle fiber bundles pre-equilibrated with 5 mM MgATP, and inhibits the ATPase activity of skeletal muscle actomyosin. It thus appears that the potentiating action of deoxycholate on the contraction of thick glycerol-extracted fiber bundles is due to its ability to enhance the diffusion of ATP through the fiber bundle.

Isometric contraction in glycerinated skeletal muscle of horseshoe crab and rabbit—I. Relation of tension to muscle fiber dimensions

1. 1. Final isometric tension of glycerinated rabbit and horseshoe crab muscle was found to be linearly related to circumference of the fiber bundle to greater than 1·0 mm circumference but not to cross-sectional area. By expressing specific tension as a function of circumference rather than area the mean deviation was lowered. 2. 2. This behaviour is explained as being dependent on the diffusion of ATP into individual fibers. The use of high ATP concentrations, active stirring and the elimination of prior soaking leads to complete activation of the fiber. Under these conditions tension is produced by rabbit fibers which is comparable to that in the live animal. 3. 3. Horseshoe crab muscle produces only a fraction of the tension found in rabbit muscle. This difference is apparently related to its extremely different structure. 4. 4. Latency, or the time between addition of ATP and onset of contraction is greatly increased by soaking the fiber bundle in buffer prior to the experiment. Rabbit fibers have the same latency period as Limulus, but the tension they produce is greatly reduced by soaking while Limulus fibers are unaffected.

Rigor contraction and the effect of various phosphate compounds on glycerinated insect flight and vertebrate muscle.

1. Glycerol-extracted flight muscle from the giant water-bug, Lethocerus cordofanus, undergoes contraction when deprived of ATP. This rigor contraction occurs in the presence of the calcium chelating agent EGTA, under conditions in which the predicted free calcium ion concentration is less than 5 x 10(-9)M. A mechanically similar contraction has been observed by depriving the muscle of Mg(2+), in the presence of 5 mM-ATP.2. In the rigor contraction tensions of up to 120 mN/mm(2) under isometric conditions, and shortenings of between 2(1/2) and 6% under isotonic conditions, have been observed at 20 degrees C.3. Muscles in rigor can be relaxed by the addition of ATP. The minimum concentration of ATP required to give full relaxation depends upon other ionic constituents of the solutions, and upon temperature, but is between 0.3 and 1 mM at 20 degrees C. Lower concentrations result in partial reduction of tension and stiffness.4. Pyrophosphate (PP) causes a reduction in the tension of muscle which has developed rigor under isometric conditions, but the stiffness, when measured at frequencies between 1 and 100 Hz, remains indistinguishable from that of rigor muscle. The stiffness when measured by applying slow length changes is comparable to that of ATP-relaxed muscle. It is suggested that in PP-relaxed muscle the cross-bridges remain in close proximity to, but are not rigidly attached to, the I filaments, resulting in a high viscous interaction between the two sets of filaments.5. The addition of low concentrations of ADP (less than about 0.7 mM) to rigor muscle in the absence of ATP causes an increase in tension. The effect is sigmoid, and is probably due to the formation of low concentrations of ATP throughout the body of the fibre by myokinase activity. Larger concentrations of ADP (about 5 mM) added to rigor muscle cause relaxation, probably due to the formation of higher ATP concentrations.6. AMP and inorganic orthophosphate have little effect upon the mechanical properties of rigor muscle.7. There is a delay of about 1 min before the onset of rigor contraction when fibres are transferred from an ATP-solution to one containing no ATP, due to the transfer of ATP in the body of the fibres. Both ATP hydrolysis by the fibres and diffusion of ATP into the bathing solution contribute significantly to the rate of depletion of ATP.8. Rabbit psoas muscle shows a similar rigor contraction in the presence of EGTA, and has mechanical properties similar to those described for Lethocerus flight muscle in the presence of pyrophosphate.

Dependence of activity of myofibrillar ATPase on sarcomere length and calcium ion concentration.

Glycerol-treated muscle fiber bundles were prepared mainly by storage in 50 per cent glycerol at −10°C for about 3 months. Their ATPase [EC 3.6. 1.3] activity was measured in the presence of 50 mM KCI, 2 to 3.35 mM MgCl2 and 20 mM Tris-maleate buffer at pH 7.0 and 25°C during an isometric contraction induced by ATP. Pyruvate kinase [EC 2.7.1.40] was coupled with myofibrillar ATPase, and the activity was measured by determining the amount of pyruvate liberated. The process of liberation of pyruvate from fiber bundles was linear with time in all the measurements. The ATPase activity of fiber bundles of about 300 μ in diameter and 2.2 to 2.6 μ in sarcomere length was independent of the concentration of phosphoenol pyruvate between 0.5 and 3.0 mM and the concentration of pyruvate kinase between 5 and 32 μg per ml, in the presence of 0.6mM ATP. Furthermore, in the presence of 1.0 mM phosphoenol pyruvate and 65 μg pyruvate kinase per ml, the activity was scarcely affected by an increase in concentration of ATP from 0.6 to 5.0 mM. The ATPase activity of fiber bundles of 250 to 310 μ in diameter and 4.2 to 5.3 μ in sarcomere length was independent of the concentration of ATP between 0.22 and 0.77 mM or of that of phosphoenol pyruvate between 0.5 and 1.0 mM, if the amounts of other constituents were sufficient. The activity of fiber bundles of 240 to 310 μ in diameter and 0.8 to 0.9 μ in sarcomere length was not affected by increase in the concentration of pyruvate kinase from 25 to 250 μg per ml or that of ATP from 2.35 to 5.0 mM. The activity in 0.6 mM ATP was almost equal to that in 2.35 mM ATP. Thus, it was concluded that the diffusion of ATP and phosphoenol pyruvate was not the limiting factor in the hydrolysis of ATP, if fiber bundles of less than 300 μ in diameter were used in the presence of at least 0.6 mM ATP and 1.0 mM phosphoenol pyruvate. The fiber bundles showed the maximum activity of 100 μmoles pyruvate per minute per g of protein at sarcomere lengths of 2.0 to2.5 μ. As the sarcomere length increased beyond 2.5 μ, the activity decreased and reached about 30 uμmoles pyruvate per minute per g of protein at sarcomere lengths of more than 4 μ. In the region where the sarcomere length was less than 2.0 μ, the ATPase activity decreased as the sarcomere length decreased, and, at a sarcomere length of 1 μ, it showed a quarter to a third of the maximum activity. These results suggested that both ATPase activity and tension development are coupled with the movement of myosin filaments past actin filaments. The maximum activity observed at sarcomere lengths of 2.0 to 2.5 μ was only one fourth of the activity of the actomyosin type of isolated acto-myosin. The dependence on Ca++ concentration of the ATPase of glycerol-treated muscle fiber bundles, which had been stored for about 3 months, was investigated at fixed sarcomere lengths of 2.0 to 2.6 μ. When Ca++ was removed by EGTA, the activity was about 48 μmoles pyruvate per minute per g of protein, and in the presence of 1 mM Ca++ it was 116 μmoles pyruvate per minute per g of protein. The concentration of Ca++ for the half maximum activation was about 0.04 μM. In the presence of 1 to 2mM EGTA, the activity of fiber bundles stored for 3 to 13 days was only 17 μmoles pyruvate per minute per g of protein, and that of those stored for about 9 months was 126 μmoles pyruvate per minute per g of protein.

A study of diffusion of ATP through glycerol-treated muscle

One and two m M ATP will penetrate bundles of glycerol-treated muscle fibers of about 100 μ thickness. This conclusion has been reached from studies by a physical method which involves recording the tension developed during ATP-induced isometric contraction. The method cannot be used to determine the precise diffusion coefficient through rabbit psoas muscle because the fibers are not thick enough to provide sufficiently long pathways for complete absence of substrate in the central core at substrate concentrations high enough to get measurable tension. It can be used, however, to compute the diffusion coefficient of ATP through this muscular material necessary to maintain a concentration of ATP in the center of fibers equal to 1 10 that of the concentration in the bath. The value obtained, 1.4–2.0 × 10 −6 sq. cm./sec., is about 100 times larger than that in the literature and one-half the free diffusion of ATP through aqueous solution. This large difference may be explained by the results of an earlier study in this laboratory of the interactions of ATP and glycerol-treated muscle which showed that the splitting of ATP by myosin was affected more by diffusion than was the change in length of bundles of muscle during isotonic ATP-induced contractions.

Spontaneous relaxation in glycerol-extracted muscle fiber bundles.

ArticleSpontaneous Relaxation in Glycerol-Extracted Muscle Fiber BundlesR. E. RanneyR. E. RanneyFrom the Department of Physiology, University of Colorado School of Medicine, Denver, ColoradoPublished Online:01 Oct 1954https://doi.org/10.1152/ajplegacy.1954.179.1.99MoreSectionsPDF (896 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByThermal effect of interaction between ATP and relaxed and contracted glycerinized fibersBulletin of Experimental Biology and Medicine, Vol. 84, No. 3Role of magnesium and calcium in the first and second contraction of glycerin-extracted muscle fibers1 May 2002 | Biochemistry, Vol. 10, No. 13A study of diffusion of ATP through glycerol-treated muscleArchives of Biochemistry and Biophysics, Vol. 102, No. 2Adenosine triphosphate-induced isometric tension in glycerol-extracted muscle fibers in relation to the cross-sectional area of their myofilamentsBiochimica et Biophysica Acta, Vol. 60, No. 2On the Contraction of Glycerol-extracted Muscle Fibre Bundles under Highly Isometric Conditions.Acta Physiologica Scandinavica, Vol. 41, No. 2-3Reaction Rates of a Muscle Model with NucleotidesScience, Vol. 122, No. 3171 More from this issue > Volume 179Issue 1October 1954Pages 99-103 Copyright & PermissionsCopyright © 1954 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1954.179.1.99PubMed13207394History Received 18 April 1954 Published online 1 October 1954 Published in print 1 October 1954 Metrics