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Journal articles on the topic 'Contraction'

Author: Grafiati

Published: 4 June 2021

Last updated: 25 July 2025

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1

Hogan, Michael C., Erica Ingham, and S. Sadi Kurdak. "Contraction duration affects metabolic energy cost and fatigue in skeletal muscle." American Journal of Physiology-Endocrinology and Metabolism 274, no. 3 (1998): E397—E402. http://dx.doi.org/10.1152/ajpendo.1998.274.3.e397.

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It has been suggested that during a skeletal muscle contraction the metabolic energy cost at the onset may be greater than the energy cost related to holding steady-state force. The purpose of the present study was to investigate the effect of contraction duration on the metabolic energy cost and fatigue process in fully perfused contracting muscle in situ. Canine gastrocnemius muscle ( n = 6) was isolated, and two contractile periods (3 min of isometric, tetanic contractions with 45-min rest between) were conducted by each muscle in a balanced order design. The two contractile periods had sti

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2

Conley, Kevin E., and Stan L. Lindstedt. "Energy-saving mechanisms in muscle: the minimization strategy." Journal of Experimental Biology 205, no. 15 (2002): 2175–81. http://dx.doi.org/10.1242/jeb.205.15.2175.

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SUMMARYMany mechanisms reduce the cost of muscle activity. Here, we describe a set of specializations that reduce the cost of contraction in the high-frequency twitches that are used by a wide variety of animals for either sound production or flight. Minimizing the cost of these contractions means that cellular ATP production can meet ATP demand and sustain the high contractile rate. Two classes of specialization are found that minimize the contractile cost. The first class reduces the muscle work required per contraction. Light appendages such as rattles, insect limbs and membranous wings tha

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3

C. Ushabhavani. "On Certain Fixed Points for (α,φ,F)-Contraction on S_b- Metric Spaces with Applications". Advances in Nonlinear Variational Inequalities 27, № 2 (2024): 360–74. http://dx.doi.org/10.52783/anvi.v27.972.

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This work establishes unique fixed point theorems (UFPT) for self mapping in complete S_b-metric spaces (S_b-MS) with the concept of (α,φ,F)-contraction in the context of S_b-MS Furthermore, we show how the results may be used and present applications to integral equations and homotopy theory. Introduction: In previous work authors were discussed fixed pointon various metric spaces with F -contractions, α-type almost -F- contractions, α-type F -Suzuki contractions, (φ, F)-contraction, F - weak contractions, α −ψ-contractive type, α −ψ-Meir-Keeler contractive mapping, α-ratonal contractive mapp

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4

Hogan, Michael C., Bruno Grassi, Michele Samaja, Creed M. Stary, and L. B. Gladden. "Effect of contraction frequency on the contractile and noncontractile phases of muscle venous blood flow." Journal of Applied Physiology 95, no. 3 (2003): 1139–44. http://dx.doi.org/10.1152/japplphysiol.00226.2003.

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The purpose of this study was to test the hypothesis that increasing muscle contraction frequency, which alters the duty cycle and metabolic rate, would increase the contribution of the contractile phase to mean venous blood flow in isolated skeletal muscle during rhythmic contractions. Canine gastrocnemius muscle ( n = 5) was isolated, and 3-min stimulation periods of isometric, tetanic contractions were elicited sequentially at rates of 0.25, 0.33, and 0.5 contractions/s. The O2 uptake, tension-time integral, and mean venous blood flow increased significantly ( P < 0.05) with each contrac

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V. Rajitha. "Tripled Fixed Point Results in G_b-Metric Spaces." Communications on Applied Nonlinear Analysis 31, no. 8s (2024): 433–40. http://dx.doi.org/10.52783/cana.v31.1536.

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In recent work authors were discussed fixed point results with various contractions like (ψ,ϕ)-weakly contractive mappings, cyclic contraction, E.A property, Suzuki-type contraction etc. in complete -metric spaces, With the help of completeness property and continuous function we obtained unique tripled fixed point in -metric spaces. Objectives: To show tripled fixed point theorems in -metric spaces via new type of contraction and shown illustrate an example which supports the main result. Methods: In recent work authors were discussed fixed point results with various contractions like (ψ, ϕ)-

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Zuo, Li, Leonardo Nogueira, and Michael C. Hogan. "Reactive oxygen species formation during tetanic contractions in single isolated Xenopus myofibers." Journal of Applied Physiology 111, no. 3 (2011): 898–904. http://dx.doi.org/10.1152/japplphysiol.00398.2011.

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Contracting skeletal muscle produces reactive oxygen species (ROS) that have been shown to affect muscle function and adaptation. However, real-time measurement of ROS in contracting myofibers has proven to be difficult. We used amphibian ( Xenopus laevis) muscle to test the hypothesis that ROS are formed during contractile activity in isolated single skeletal muscle fibers and that this contraction-induced ROS formation affects fatigue development. Single myofibers were loaded with 5 μM dihydrofluorescein-DA (Hfluor-DA), a fluorescent probe that reacts with ROS and results in the formation of

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7

Hamann, Jason J., Heidi A. Kluess, John B. Buckwalter, and Philip S. Clifford. "Blood flow response to muscle contractions is more closely related to metabolic rate than contractile work." Journal of Applied Physiology 98, no. 6 (2005): 2096–100. http://dx.doi.org/10.1152/japplphysiol.00400.2004.

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The magnitude of the blood flow response to exercise has been linked to both the contractile work performed and the metabolic cost of the activity. Under certain conditions, contractile work and metabolic cost may be dissociated. This study examined the blood flow response to trains of contractions when contraction duration was manipulated under conditions of similar tension-time indexes (isometric analog of work). Previous investigations have shown that trains of short-duration contractions have a greater ATP utilization, which may result from an augmented ion transport required for muscle ac

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8

Kavvampalli Jyothirmayi Rani. "Some Applications via Coupled Fixed Point Theorems for (????, ????)-H-Contraction Mappings in Partial b- Metric Spaces." Communications on Applied Nonlinear Analysis 31, no. 5s (2024): 351–71. http://dx.doi.org/10.52783/cana.v31.1055.

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This work establishes unique common coupled fixed point theorems for given mapping in complete partial b-metric spaces with the concept of (α, ϕ)-H-contraction in the context of partial b-metric spaces. (α, ϕ)-H-contraction Furthermore, we show how the results may be used and present applications to integral equations and Homotopy theory. Introduction In previous work, authors have discussed various fixed point theorems on partial b-metric spaces with (ψ, ϕ)-weakly contractive mappings, α−ψ-contractive type, Suzuki type contractions, rational contraction and H-weak contractions. In our work, w

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9

Meisner, Joshua K., Randolph H. Stewart, Glen A. Laine, and Christopher M. Quick. "Lymphatic vessels transition to state of summation above a critical contraction frequency." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 293, no. 1 (2007): R200—R208. http://dx.doi.org/10.1152/ajpregu.00468.2006.

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Although behavior of lymphatic vessels is analogous to that of ventricles, which completely relax between contractions, and blood vessels, which maintain a tonic constriction, the mixture of contractile properties can yield behavior unique to lymphatic vessels. In particular, because of their limited refractory period and slow rate of relaxation, lymphatic vessels lack the contractile properties that minimize summation in ventricles. We, therefore, hypothesized that lymphatic vessels transition to a state of summation when lymphatic vessel contraction frequency exceeds a critical value. We use

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10

Pant, Rajendra, and Hemant Nashine. "Fractals of FG-Hutchinson Barnsley operator in metric spaces." Filomat 38, no. 27 (2024): 9711–25. https://doi.org/10.2298/fil2427711p.

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The goal of this work is to build fractals using a finite family of F G-contraction mappings. This class of mappings is more general than Banach contraction, F-contraction, Geraghty-contraction, rational-type contraction and many other contractions on metric spaces. We derive several consequence of our main result and discuss certain iterated function systems that fulfil a specific set of contractive requirements. Several examples are presented with accompanying graphics to substantiate the findings obtained here. Our results integrate, generalize, and extend previous work in this area.

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11

Siegle, M. L., and H. J. Ehrlein. "Interdigestive contractile patterns of the ileum in dogs." American Journal of Physiology-Gastrointestinal and Liver Physiology 253, no. 4 (1987): G452—G460. http://dx.doi.org/10.1152/ajpgi.1987.253.4.g452.

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The aim of this study is to elucidate the nature of ileal interdigestive contractile patterns by the computerized analysis of the contraction spread and by videofluoroscopy. Conscious dogs equipped with closely spaced strain-gauge force transducers were used. Two patterns of repetitive, phasic contractions were recorded, migrating clusters and phase IIIs; both patterns consisted of repetitive, propagated contractions. Both patterns migrated aborad by sequential movement of contraction waves down the bowel. Consequently, the rate of migration of either of the entire patterns was slower than the

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12

Todd, Gabrielle, Janet L. Taylor, Jane E. Butler, Peter G. Martin, Robert B. Gorman, and Simon C. Gandevia. "Use of motor cortex stimulation to measure simultaneously the changes in dynamic muscle properties and voluntary activation in human muscles." Journal of Applied Physiology 102, no. 5 (2007): 1756–66. http://dx.doi.org/10.1152/japplphysiol.00962.2006.

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Force responses to transcranial magnetic stimulation of motor cortex (TMS) during exercise provide information about voluntary activation and contractile properties of the muscle. Here, TMS-generated twitches and muscle relaxation during the TMS-evoked silent period were measured in fresh, heated, and fatigued muscle. Subjects performed isometric contractions of elbow flexors in two studies. Torque and EMG were recorded from elbow flexor and extensor muscles. One study ( n = 6) measured muscle contraction times and relaxation rates during brief maximal and submaximal contractions in fresh and

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13

Mehta, D., M. F. Wu, and S. J. Gunst. "Role of contractile protein activation in the length-dependent modulation of tracheal smooth muscle force." American Journal of Physiology-Cell Physiology 270, no. 1 (1996): C243—C252. http://dx.doi.org/10.1152/ajpcell.1996.270.1.c243.

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The active isometric force developed by a muscle decreases at muscle lengths below an optimal length (Lo). However, when the length of an actively contracting muscle is abruptly decreased, a lower level of isometric force is reached during force redevelopment than when the contraction is initiated at the shorter length. This has been attributed to a deactivation of contractile proteins caused by shortening. In this study, intracellular Ca2+ and myosin light chain (MLC) phosphorylation were measured to assess the mechanisms for the modulation of isometric force caused by changing smooth muscle

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14

Szarek, J. L., and N. L. Schmidt. "Hydrogen peroxide-induced potentiation of contractile responses in isolated rat airways." American Journal of Physiology-Lung Cellular and Molecular Physiology 258, no. 4 (1990): L232—L237. http://dx.doi.org/10.1152/ajplung.1990.258.4.l232.

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We hypothesized that metabolites of O2 may play a role in the development of airway hyperreactivity and undertook this study to examine the effects of one of these metabolites, hydrogen peroxide (H2O2), on electrical field stimulation-induced contractile responses of isolated rat intrapulmonary bronchi. Exposure to H2O2 (1 mM) elicited a transient contractile response with a peak response equivalent to 18.1 +/- 2.0% of the reference contraction obtained to electrical stimulation. The H2O2-induced contraction was attenuated by pretreatment of tissues with indomethacin and superoxide dismutase,

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AlMohimeed, Ibrahim, and Yuu Ono. "Ultrasound Measurement of Skeletal Muscle Contractile Parameters Using Flexible and Wearable Single-Element Ultrasonic Sensor." Sensors 20, no. 13 (2020): 3616. http://dx.doi.org/10.3390/s20133616.

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Skeletal muscle is considered as a near-constant volume system, and the contractions of the muscle are related to the changes in tissue thickness. Assessment of the skeletal muscle contractile parameters such as maximum contraction thickness ( T h ), contraction time ( T c ), contraction velocity ( V c ), sustain time ( T s ), and half-relaxation ( T r ) provides valuable information for various medical applications. This paper presents a single-element wearable ultrasonic sensor (WUS) and a method to measure the skeletal muscle contractile parameters in A-mode ultrasonic data acquisition. The

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Kato, Tatsuya, Atsushi Sasaki, Hikaru Yokoyama, Matija Milosevic, and Kimitaka Nakazawa. "Effects of neuromuscular electrical stimulation and voluntary commands on the spinal reflex excitability of remote limb muscles." Experimental Brain Research 237, no. 12 (2019): 3195–205. http://dx.doi.org/10.1007/s00221-019-05660-6.

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Abstract It is well known that contracting the upper limbs can affect spinal reflexes of the lower limb muscle, via intraneuronal networks within the central nervous system. However, it remains unknown whether neuromuscular electrical stimulation (NMES), which can generate muscle contractions without central commands from the cortex, can also play a role in such inter-limb facilitation. Therefore, the objective of this study was to compare the effects of unilateral upper limb contractions using NMES and voluntary unilateral upper limb contractions on the inter-limb spinal reflex facilitation i

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17

Faas, Henryk, Geoffrey S. Hebbard, Christine Feinle, et al. "Pressure-geometry relationship in the antroduodenal region in humans." American Journal of Physiology-Gastrointestinal and Liver Physiology 281, no. 5 (2001): G1214—G1220. http://dx.doi.org/10.1152/ajpgi.2001.281.5.g1214.

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Understanding of the control mechanisms underlying gastric motor function is still limited. The aim of the present study was to evaluate antral pressure-geometry relationships during gastric emptying slowed by intraduodenal nutrient infusion and enhanced by erythromycin. In seven healthy subjects, antral contractile activity was assessed by combined dynamic magnetic resonance imaging and antroduodenal high-resolution manometry. After intragastric administration of a 20% glucose solution (750 ml), gastric motility and emptying were recorded during intraduodenal nutrient infusion alone and, subs

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Tamura, Yuki, Karina Kouzaki, Takaya Kotani, and Koichi Nakazato. "Electrically stimulated contractile activity-induced transcriptomic responses and metabolic remodeling in C2C12 myotubes: twitch vs. tetanic contractions." American Journal of Physiology-Cell Physiology 319, no. 6 (2020): C1029—C1044. http://dx.doi.org/10.1152/ajpcell.00494.2019.

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The contraction of myotubes using electrical pulse stimulation is a research tool used to mimic muscle contractile activity and exercise in rodents and humans. Most protocols employed in previous work used low-frequency twitch contractions. However, high-frequency tetanus contractions that are more physiologically relevant to muscle contractions in vivo are poorly characterized. In this report, the similarities and differences in acute responses and chronic adaptations with different contractile modes using twitches (2 Hz, continuous, 3 h) and tetanus (66 Hz, on: 5 s/off: 5 s, 3 h) were invest

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Lou, F., N. A. Curtin, and R. C. Woledge. "Elastic energy storage and release in white muscle from dogfish scyliorhinus canicula." Journal of Experimental Biology 202, no. 2 (1999): 135–42. http://dx.doi.org/10.1242/jeb.202.2.135.

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The production of work by the contractile component (CC) and the storage and release of work in the elastic structures that act in series (the series elastic component, SEC) with the contractile component were measured using white muscle fibres from the dogfish Scyliorhinus canicula. Heat production was also measured because the sum of work and heat is equivalent to the energy cost of the contraction (ATP used). These energy fluxes were evaluated in contractions with constant-velocity shortening either during stimulation or during relaxation. The muscle preparation was tetanized for 0.6 s and

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Wang, Wei, Zhanna Nepiyushchikh, David C. Zawieja, et al. "Inhibition of myosin light chain phosphorylation decreases rat mesenteric lymphatic contractile activity." American Journal of Physiology-Heart and Circulatory Physiology 297, no. 2 (2009): H726—H734. http://dx.doi.org/10.1152/ajpheart.00312.2009.

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Muscular lymphatics use both phasic and tonic contractions to transport lymph for conducting their vital functions. The molecular mechanisms regulating lymphatic muscle contractions are not well understood. Based on the well-established finding that the phosphorylation of myosin light chain 20 (MLC20) plays an essential role in blood vessel smooth muscle contraction, we investigated if phosphorylated MLC20 (pMLC20) would modulate the tonic and/or phasic contractions of lymphatic muscle. The effects of ML-7, a MLC kinase inhibitor (1–10 μM), were tested on the contractile parameters of isolated

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Herdmann, J., P. Enck, P. Zacchi-Deutschbein, and U. Ostermann. "Speed and pressure characteristics of external anal sphincter contractions." American Journal of Physiology-Gastrointestinal and Liver Physiology 269, no. 2 (1995): G225—G231. http://dx.doi.org/10.1152/ajpgi.1995.269.2.g225.

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The principle of isochronism reflects constant contraction time for varying strengths of muscle contraction. This principle was studied for the innervation of the pelvic floor in humans using motor-evoked potentials (MEPs) and evoked pressure curves (EPCs) from the external anal sphincter muscle (EAS). MEPs and EPCs were simultaneously recorded after transcranial magnetic stimulation of the motor cortex. Voluntary contractions were also studied. Contraction times of the EAS were significantly longer in voluntary contractions (mean, 237 ms) than in EPCs (mean, 90 ms). Depending on either mode o

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Hasibuan, Zainuddin. "Contractions Used in “Maleficent” Movie." Journal Polingua : Scientific Journal of Linguistics, Literature and Education 2, no. 2 (2016): 15–23. http://dx.doi.org/10.30630/polingua.v6i2.82.

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The tiltle of this research is “Contractions Used in Maleficent Movie”. “Maleficent” movie was directed by Robert Stromberg based on the originally story Disney's Sleeping Beauty La Belle au bois dormant by Charles Perrault. The background of this research, there are many contractions in “Maleficent” movie. This is good to learn and to use them (contractions) in daily life and maybe they are not found in other movies. The contraction spoken by movie players is sometimes very difficult to understand. The researcher choose this movie because this movie is so interest and inspire. The problem of

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23

Waldrop, T. G., and R. W. Stremel. "Muscular contraction stimulates posterior hypothalamic neurons." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 256, no. 2 (1989): R348—R356. http://dx.doi.org/10.1152/ajpregu.1989.256.2.r348.

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Recent studies have suggested that the subthalamic locomotor region (STLR) of the posterior hypothalamus is involved in modulating cardiorespiratory responses to feedback from contracting muscles. The purpose of this study was to determine whether neurons in this hypothalamic region alter their discharge frequency during contraction of hindlimb muscles. Stainless steel electrodes were used to record single-unit activity of STLR neurons during static and rhythmic contractions of hindlimb muscles in anesthetized cats. Recordings were also made from neurons in areas outside but surrounding the su

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Kelley, C., P. D'Amore, H. B. Hechtman, and D. Shepro. "Microvascular pericyte contractility in vitro: comparison with other cells of the vascular wall." Journal of Cell Biology 104, no. 3 (1987): 483–90. http://dx.doi.org/10.1083/jcb.104.3.483.

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Collagen lattices containing bovine retinal pericytes (RPs), vascular smooth muscle cells (VSMCs), pulmonary microvessel endothelial cells (PMECs), or aortic endothelial cells (AECs) were prepared and contraction was quantitated by measuring the resulting change in lattice area. VSMCs were the most efficient at lattice contraction followed by RPs and then PMECs. AECs did not contract the lattices. To document further that these observations represent contraction, cells were grown on inert silicone rubber sheets. Substratum wrinkling was indicative of tension development and quantitated as perc

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Slabaugh, Jessica L., Lucia Brunello, Sandor Gyorke, and Paul M. L. Janssen. "Contractile parameters and occurrence of alternans in isolated rat myocardium at supra-physiological stimulation frequency." American Journal of Physiology-Heart and Circulatory Physiology 302, no. 11 (2012): H2267—H2275. http://dx.doi.org/10.1152/ajpheart.01004.2011.

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The cardiac refractory period prevents the heart from tetanic activation that is typically used in noncardiac striated muscle tissue. To what extent the refractory period prevents successive action potentials to activate the excitation-contraction coupling process and contractile machinery at supra-physiological rates, such as those present during ventricular fibrillation, is unknown. Using multicellular trabeculae isolated from rat hearts, we studied amplitude and kinetics of contraction at rates well above the normal in vivo rat heart range. We show that even at twice the maximal heart rate

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Xu, Hao, Ping Zhao, Wen-Jing Zhang, et al. "Generation and Role of Oscillatory Contractions in Mouse Airway Smooth Muscle." Cellular Physiology and Biochemistry 47, no. 4 (2018): 1546–55. http://dx.doi.org/10.1159/000490873.

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Background/Aims: Tetraethylammonium chloride (TEA) induces oscillatory contractions in mouse airway smooth muscle (ASM); however, the generation and maintenance of oscillatory contractions and their role in ASM are unclear. Methods: In this study, oscillations of ASM contraction and intracellular Ca2+ were measured using force measuring and Ca2+ imaging technique, respectively. TEA, nifedipine, niflumic acid, acetylcholine chloride, lithium chloride, KB-R7943, ouabain, 2-Aminoethoxydiphenyl borate, thapsigargin, tetrodotoxin, and ryanodine were used to assess the mechanism of oscillatory contr

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Honoré, E., M. M. Adamantidis, B. A. Dupuis, C. E. Challice, and P. Guilbault. "Calcium channels and excitation–contraction coupling in cardiac cells. I. Two components of contraction in guinea-pig papillary muscle." Canadian Journal of Physiology and Pharmacology 65, no. 9 (1987): 1821–31. http://dx.doi.org/10.1139/y87-284.

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Biphasic contractions have been obtained in guinea-pig papillary muscle by inducing partial depolarization in K+-rich solution (17 mM) containing 0.3 μM isoproterenol; whereas in guinea-pig atria, the same conditions led to monophasic contractions corresponding to the first component of contraction in papillary muscle. The relationships between the amplitude of the two components of the biphasic contraction and the resting membrane potential were sigmoidal curves. The first component of contraction was inactivated for membrane potentials less positive than those for the second component. In Na

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Thomas, G. D., J. Hansen, and R. G. Victor. "Inhibition of alpha 2-adrenergic vasoconstriction during contraction of glycolytic, not oxidative, rat hindlimb muscle." American Journal of Physiology-Heart and Circulatory Physiology 266, no. 3 (1994): H920—H929. http://dx.doi.org/10.1152/ajpheart.1994.266.3.h920.

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Previous studies have produced conflicting evidence as to whether sympathetic vasoconstriction is impaired in active skeletal muscle. Because alpha 2-, not alpha 1-, adrenergic vasoconstriction is attenuated by mild acidosis, we hypothesized that alpha 2-mediated sympathetic vasoconstriction would be attenuated in contracting glycolytic muscle, which produces more acidosis than oxidative muscle. We compared effects of lumbar sympathetic nerve stimulation and alpha-adrenergic agonists on arterial pressure, femoral blood flow, and force output during contractions of oxidative or glycolytic muscl

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Pelaez, Nancy J., Tracey R. Braun, Richard J. Paul, Richard A. Meiss, and C. Subah Packer. "H2O2 mediates Ca2+- and MLC20phosphorylation-independent contraction in intact and permeabilized vascular muscle." American Journal of Physiology-Heart and Circulatory Physiology 279, no. 3 (2000): H1185—H1193. http://dx.doi.org/10.1152/ajpheart.2000.279.3.h1185.

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One purpose of the current study was to establish whether vasoconstriction occurs in all vessel types in response to H2O2. Isometric force was measured in pulmonary venous and arterial rings, and isobaric contractions were measured in mesenteric arteries and veins in response to H2O2. A second purpose was to determine whether H2O2-induced contraction is calcium independent. The addition of H2O2 to calcium-depleted (using the Ca2+ ionophore ionomycin in zero calcium EGTA buffer) muscle caused contraction. Furthermore, permeabilized muscle contracted in response to H2O2 even in zero Ca2+. The fi

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K. Varalakshmi. "Fixed Point Results in G Metric Space via Α-Series". Communications on Applied Nonlinear Analysis 32, № 6s (2025): 275–89. https://doi.org/10.52783/cana.v32.3294.

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Introduction: Mustafa and sims [1] introduced the concept of G-metric space in 2005. Afterwards, Mustafa et al and many authors [3]-[19] obtained some common fixed-point theorems, coupled and tripled fixed point results for mappings satisfying different contractive conditions in G metric space. In this study we prove fixed point results in G metric space via α-series by using some conditions that are a sequence of a mappings and a self-mapping. Objectives: To show tripled fixed-point theorems and common fixed point theorems by using sequence of mappings and self a self-mapping via α-series and

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Herrera, Gerald M., Thomas J. Heppner, and Mark T. Nelson. "Regulation of urinary bladder smooth muscle contractions by ryanodine receptors and BK and SK channels." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 279, no. 1 (2000): R60—R68. http://dx.doi.org/10.1152/ajpregu.2000.279.1.r60.

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This study examines the roles of voltage-dependent Ca2+ channels (VDCC), ryanodine receptors (RyRs), large-conductance Ca2+-activated K+ (BK) channels, and small-conductance Ca2+-activated K+ (SK) channels in the regulation of phasic contractions of guinea pig urinary bladder smooth muscle (UBSM). Nisoldipine (100 nM), a dihydropyridine inhibitor of VDCC, abolished spontaneous UBSM contractions. Ryanodine (10 μM) increased contraction frequency and thereby integrated force and, in the presence of the SK blocker apamin, had a greater effect on integrated force than ryanodine alone. Blocking BK

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Goodyear, L. J., P. A. King, M. F. Hirshman, C. M. Thompson, E. D. Horton, and E. S. Horton. "Contractile activity increases plasma membrane glucose transporters in absence of insulin." American Journal of Physiology-Endocrinology and Metabolism 258, no. 4 (1990): E667—E672. http://dx.doi.org/10.1152/ajpendo.1990.258.4.e667.

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To study the interactions between insulin and contraction on the skeletal muscle glucose transport system, the hindquarters of male rats were perfused in the absence of insulin, in the presence of insulin (30 mU/ml), during contractions induced by sciatic nerve stimulation, or during contractions plus insulin. Compared with control preparations, rates of glucose uptake in the perfused hindquarter were increased by 2.5- and 2.6-fold in the insulin and insulin plus contraction groups, respectively, but not significantly increased in the contraction only preparations. After perfusion, soleus and

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Sosnowska, Anna J., Aleksandra Vuckovic, and Henrik Gollee. "Automated semi-real-time detection of muscle activity with ultrasound imaging." Medical & Biological Engineering & Computing 59, no. 9 (2021): 1961–71. http://dx.doi.org/10.1007/s11517-021-02407-w.

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AbstractUltrasound imaging (USI) biofeedback is a useful therapeutic tool; however, it relies on qualitative assessment by a trained therapist, while existing automatic analysis techniques are computationally demanding. This study aims to present a computationally inexpensive algorithm based on the difference in pixel intensity between USI frames. During an offline experiment, where data was analyzed after the study, participants performed isometric contractions of the gastrocnemius medialis (GM) muscle, as executed (30% of maximum contraction) or attempted (low force contraction up to a point

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Zawieja, D. C., K. L. Davis, R. Schuster, W. M. Hinds, and H. J. Granger. "Distribution, propagation, and coordination of contractile activity in lymphatics." American Journal of Physiology-Heart and Circulatory Physiology 264, no. 4 (1993): H1283—H1291. http://dx.doi.org/10.1152/ajpheart.1993.264.4.h1283.

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The propagation and coordination of lymphatic contractions were studied in the mesentery of the rat small intestine using in situ microscopic observation. Indexes of lymphatic diameter were simultaneously measured at two adjacent lymphangions in spontaneously contracting lymphatics (n = 51). Diameter index, contraction frequency, and the percentage of the intersegmental contractions that were propagated and coordinated (PP) were determined at both sites. The conduction velocity of the contractile activity and the percentage of the coordinated contractions that were propagated both antegrade to

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Pal, Anupam, and James G. Brasseur. "The Mechanical Advantage of Local Longitudinal Shortening on Peristaltic Transport." Journal of Biomechanical Engineering 124, no. 1 (2001): 94–100. http://dx.doi.org/10.1115/1.1427700.

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Whereas bolus transport along the esophagus results from peristaltic contractions of the circular muscle layer, it has been suggested that local shortening of the longitudinal muscle layer concentrates circular muscle fibers in the region where the highest contractile pressures are required. Here we analyze the mechanical consequences of local longitudinal shortening (LLS) through a mathematical model based on lubrication theory. We find that local pressure and shear stress in the contraction zone are greatly reduced by the existence of LLS. In consequence, peak contractile pressure is reduced

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Sekizawa, K., J. Tamaoki, J. A. Nadel, and D. B. Borson. "Enkephalinase inhibitor potentiates substance P- and electrically induced contraction in ferret trachea." Journal of Applied Physiology 63, no. 4 (1987): 1401–5. http://dx.doi.org/10.1152/jappl.1987.63.4.1401.

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To determine the role of endogenous enkephalinase (EC 3.4.24.11) in regulating peptide-induced contraction of airway smooth muscle, we studied the effect of the enkephalinase inhibitor, leucine-thiorphan (Leu-thiorphan), on responses of isolated ferret tracheal smooth muscle segments to substance P (SP) and to electrical field stimulation (EFS). Leu-thiorphan shifted the dose-response curve to SP to lower concentrations. Atropine or the SP antagonist [D-Pro2,D-Trp7,9]SP significantly inhibited SP-induced contractions in the presence of Leu-thiorphan. Leu-thiorphan increased the contractile res

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Stebbins, C. L., O. A. Carretero, T. Mindroiu, and J. C. Longhurst. "Bradykinin release from contracting skeletal muscle of the cat." Journal of Applied Physiology 69, no. 4 (1990): 1225–30. http://dx.doi.org/10.1152/jappl.1990.69.4.1225.

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Results of previous studies from our laboratory suggest that bradykinin has a role in the exercise pressor reflex elicited by static muscle contraction. The purpose of this study was to quantify the release of bradykinin from contracting skeletal muscle. In 18 cats, blood samples were withdrawn directly from the venous effluent of the triceps surae muscles immediately before and after 30 s of static contraction producing peak muscle tensions of 33, 50, and 100% of maximum electrically stimulated contraction. Contractions producing muscle tensions of 50 and 100% of maximum increased muscle veno

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Di Liberto, G., E. Dallot, I. Eude-Le Parco, D. Cabrol, F. Ferré та M. Breuiller-Fouché. "A critical role for PKCζ in endothelin-1-induced uterine contractions at the end of pregnancy". American Journal of Physiology-Cell Physiology 285, № 3 (2003): C599—C607. http://dx.doi.org/10.1152/ajpcell.00040.2003.

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We have previously shown that protein kinase C (PKC) ζ and/or PKCδ are necessary for endothelin-1 (ET-1)-induced human myometrial contraction at the end of pregnancy (Eude I, Paris P, Cabrol D, Ferré F, and Breuiller-Fouché M. Biol Reprod 63: 1567–1573, 2000). Here, we report that the selective inhibitor of PKCδ isoform, Rottlerin, does not prevent ET-1-induced contractions, whereas LY-294002, a phosphatidylinositol (PI) 3-kinase inhibitor, affects the contractile response. This study characterized the in vitro contractile response of cultured human pregnant myometrial cells to ET-1 known to i

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Connelly, Denise M., Charles L. Rice, Martin R. Roos, and Anthony A. Vandervoort. "Motor unit firing rates and contractile properties in tibialis anterior of young and old men." Journal of Applied Physiology 87, no. 2 (1999): 843–52. http://dx.doi.org/10.1152/jappl.1999.87.2.843.

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The effects of aging on motoneuron firing rates and muscle contractile properties were studied in tibialis anterior muscle by comparing results from six young (20.8 ± 0.8 yr) and six old men (82.0 ± 1.7 yr). For each subject, data were collected from repeated tests over a 2-wk period. Contractile tests included maximal voluntary contraction (MVC) with twitch interpolation and stimulated twitch contractions. The old men had 26% lower MVC torque ( P < 0.01) than did the young men, but percent activation was not different (99.1 and 99.3%, respectively). Twitch contraction durations were 23% lo

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Gorcheva, Zornitsa V., Galya Ts Stavreva, Negrin N. Negrev, and Radomir G. Radomirov. "Ascending Excitatory and Inhibitory Motor Activity of Colonic Longitudinal and Circular Muscles in Rat Model." Journal of Biomedical and Clinical Research 12, no. 1 (2019): 10–18. http://dx.doi.org/10.2478/jbcr-2019-0002.

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Summary In this experiment we studied the role of excitatory and inhibitory neurotransmissions in the ascending reflex pathways in isolated rat colon. Partitioned organ bath, electrical field stimulation (EFS), drugs and isolated preparations were used to evaluate motor activity of (LM) and circular muscles (CM). Ascending motor responses of LM and CM were frequency-dependent contraction, significantly more expressed in LM. Atropine (0.3 µM) decreased ascending contractions of LM. During atropine treatment spantide (0.1 µM) further suppressed ascending contractile motor responses. In the prese

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Itemire, Anne Oghenekevwe, MacDonald Idu, Bafor Evi Enitome, Josephine Omose Ofeimun, and Benjamin Ogunma Gabriel. "Phytochemistry and Uterine Contractile Effect of VLC Fractionated Bi-herbal Formulation “Makann” in Mice." African Journal of Clinical Medicine and Pharmacy Research 2, no. 2 (2025): 204–23. https://doi.org/10.58578/ajcmpr.v2i2.5155.

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This study evaluate the phytochemistry, uterine activity of a bi-herbal formulation of G. kola and C. papaya roots in rodents. Identification of phytochemical compounds in BH was done using high performance liquid chromatography (HPLC) and fractionated with vacuum liquid chromatography and thin layer chromatography. Ex-vivo BH elicited cumulative concentrations response on spontaneous contractions of oxytocin-induced contraction in the presence and absence of calcium and potassium induced contraction. The Phytochemicals showed alkaloids (Hordenine, Cytisine, Methyl Jasmonate, Galanthamine and

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Hansson, Sven Ove. "Kernel contraction." Journal of Symbolic Logic 59, no. 3 (1994): 845–59. http://dx.doi.org/10.2307/2275912.

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AbstractKernel contraction is a natural nonrelational generalization of safe contraction. All partial meet contractions are kernel contractions, but the converse relationship does not hold. Kernel contraction is axiomatically characterized. It is shown to be better suited than partial meet contraction for formal treatments of iterated belief change.

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SARNMETA, PANITARN, and SUTHEP SUANTAI. "Global Minimization of best proximity points for semi-cyclic Berinde contractions." Carpathian Journal of Mathematics 34, no. 3 (2018): 411–16. http://dx.doi.org/10.37193/cjm.2018.03.17.

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In this paper, we introduce a semi-cyclic Berinde contraction pair on a metric space which is more general than that of semi-cyclic contraction pair defined by Gabeleh and Abkar [Gabeleh, M. and Abkar, A., Best proximity points for semi-cyclic contractive pairs in Banach spaces, Int. Math. Forum, 6 (2011), 2179–2186] and prove an existence result concerning global monomization of best proximity points of this pair. Our main result can be used to obtain a common fixed point theorem of some contractive mappings related to Berinde’s contractions without commutative assumption. An example supporti

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Dalton, Brian H., Brad Harwood, Andrew W. Davidson, and Charles L. Rice. "Triceps surae contractile properties and firing rates in the soleus of young and old men." Journal of Applied Physiology 107, no. 6 (2009): 1781–88. http://dx.doi.org/10.1152/japplphysiol.00464.2009.

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Mean maximal motor unit firing rates (MUFRs) of the human soleus are lower (5–20 Hz) than other limb muscles (20–50 Hz) during brief sustained contractions. With healthy adult aging, maximal MUFRs are 20–40% lower and twitch contractile speed of lower limb muscles are 10–40% slower compared with young adults. However, it is unknown whether the inherently low maximal MUFRs for the soleus are further reduced with aging in association with age-related slowing in contractile properties. The purpose of the present study was to compare the changes in triceps surae contractile properties and MUFRs of

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Kern, Mark K., Ronald C. Arndorfer, James S. Hyde, and Reza Shaker. "Cerebral cortical representation of external anal sphincter contraction: effect of effort." American Journal of Physiology-Gastrointestinal and Liver Physiology 286, no. 2 (2004): G304—G311. http://dx.doi.org/10.1152/ajpgi.00201.2003.

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The external anal sphincter (EAS) plays a critical role in maintaining fecal continence; however, cerebral cortical control of voluntary EAS contraction is not completely understood. Our aims were to determine the cortical areas associated with voluntary EAS contraction and to determine the effect of two levels of sphincter contraction effort on brain activity. Seventeen asymptomatic adults (ages 21-48, 9 male) were studied using functional magnetic resonance imaging (fMRI) to detect brain activity. Studies were done in two stages. In stage 1 (10 subjects, 5 male), anal sphincter pressure was

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Perez, Jose F., and Michael J. Sanderson. "The Contraction of Smooth Muscle Cells of Intrapulmonary Arterioles Is Determined by the Frequency of Ca2+ Oscillations Induced by 5-HT and KCl." Journal of General Physiology 125, no. 6 (2005): 555–67. http://dx.doi.org/10.1085/jgp.200409217.

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Increased resistance of the small blood vessels within the lungs is associated with pulmonary hypertension and results from a decrease in size induced by the contraction of their smooth muscle cells (SMCs). To study the mechanisms that regulate the contraction of intrapulmonary arteriole SMCs, the contractile and Ca2+ responses of the arteriole SMCs to 5-hydroxytrypamine (5-HT) and KCl were observed with phase-contrast and scanning confocal microscopy in thin lung slices cut from mouse lungs stiffened with agarose and gelatin. 5-HT induced a concentration-dependent contraction of the arteriole

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Mondal, Anupom, Zuoyun Xie, Yuki Miyano, et al. "Coordination of motilin and ghrelin regulates the migrating motor complex of gastrointestinal motility in Suncus murinus." American Journal of Physiology-Gastrointestinal and Liver Physiology 302, no. 10 (2012): G1207—G1215. http://dx.doi.org/10.1152/ajpgi.00379.2011.

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Motilin and ghrelin are the gastrointestinal (GI) hormones released in a fasting state to stimulate the GI motility of the migrating motor complex (MMC). We focused on coordination of the ghrelin/motilin family in gastric contraction in vivo and in vitro using the house musk shrew ( Suncus murinus ), a ghrelin- and motilin-producing mammal. To measure the contractile activity of the stomach in vivo, we recorded GI contractions either in the free-moving conscious or anesthetized S. murinus and examined the effects of administration of motilin and/or ghrelin on spontaneous MMC in the fasting sta

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James, Arlene N., James P. Ryan, and Henry P. Parkman. "Inhibitory effects of botulinum toxin on pyloric and antral smooth muscle." American Journal of Physiology-Gastrointestinal and Liver Physiology 285, no. 2 (2003): G291—G297. http://dx.doi.org/10.1152/ajpgi.00296.2002.

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Botulinum toxin injection into the pylorus is reported to improve gastric emptying in gastroparesis. Classically, botulinum toxin inhibits ACh release from cholinergic nerves in skeletal muscle. The aim of this study was to determine the effects of botulinum toxin on pyloric smooth muscle. Guinea pig pyloric muscle strips were studied in vitro. Botulinum toxin type A was added; electric field stimulation (EFS) was performed every 30 min for 6 h. ACh (100 μM)-induced contractile responses were determined before and after 6 h. Botulinum toxin caused a concentration-dependent decrease of pyloric

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Yin, Xiaoyan, Nicholas J. D. Gower, Howard A. Baylis, and Kevin Strange. "Inositol 1,4,5-Trisphosphate Signaling Regulates Rhythmic Contractile Activity of Myoepithelial Sheath Cells in Caenorhabditis elegans." Molecular Biology of the Cell 15, no. 8 (2004): 3938–49. http://dx.doi.org/10.1091/mbc.e04-03-0198.

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Intercellular communication between germ cells and neighboring somatic cells is essential for reproduction. Caenorhabditis elegans oocytes are surrounded by and coupled via gap junctions to smooth muscle-like myoepithelial sheath cells. Rhythmic sheath cell contraction drives ovulation and is triggered by a factor secreted from oocytes undergoing meiotic maturation. We demonstrate for the first time that signaling through the epidermal growth factor-like ligand LIN-3 and the LET-23 tyrosine kinase receptor induces ovulatory contractions of sheath cells. Reduction-of-function mutations in the i

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Janson, L. W., J. Kolega, and D. L. Taylor. "Modulation of contraction by gelation/solation in a reconstituted motile model." Journal of Cell Biology 114, no. 5 (1991): 1005–15. http://dx.doi.org/10.1083/jcb.114.5.1005.

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The actin-based cytoskeleton is a dynamic component of living cells with major structural and contractile properties involved in fundamental cellular processes. The action of actin-binding proteins can decrease or increase the gel structure. Changes in the actin-based cytoskeleton have long been thought to modulate the myosin II-based contractions involved in these cellular processes, but there has been some debate concerning whether maximal gelation increases or decreases contractile activity. To address this question, we have examined how contractile activity is modulated by the extent of ac

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