Ultrastructural and Functional Changes in Smooth Muscle Associated with Freezing and Thawing

2008 ◽  
pp. 271-293 ◽  
Author(s):  
C. A. Walter
Keyword(s):  
Smooth Muscle ◽  
Freezing And Thawing ◽  
Functional Changes

scholarly journals Urokinase Receptor Counteracts Vascular Smooth Muscle Cell Functional Changes Induced by Surface Topography

Theranostics ◽  
2013 ◽  
Vol 3 (7) ◽  
pp. 516-526 ◽  
Author(s):  
Yulia Kiyan ◽  
Kestutis Kurselis ◽  
Roman Kiyan ◽  
Hermann Haller ◽  
Boris N. Chichkov ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cell ◽  
Surface Topography ◽  
Muscle Cell ◽  
Vascular Smooth Muscle Cell ◽  
Urokinase Receptor ◽  
Functional Changes

scholarly journals The Na,K-ATPase-Dependent Src Kinase Signaling Changes with Mesenteric Artery Diameter

2018 ◽  
Vol 19 (9) ◽  
pp. 2489 ◽  
Author(s):  
Lin Zhang ◽  
Christian Aalkjaer ◽  
Vladimir Matchkov
Keyword(s):  
Smooth Muscle ◽  
Binding Sites ◽  
Isometric Force ◽  
Src Kinase ◽  
Ouabain Binding ◽  
Arterial Diameter ◽  
Small Arteries ◽  
Functional Changes ◽  
High Affinity ◽  
Different Diameters

Inhibition of the Na,K-ATPase by ouabain potentiates vascular tone and agonist-induced contraction. These effects of ouabain varies between different reports. In this study, we assessed whether the pro-contractile effect of ouabain changes with arterial diameter and the molecular mechanism behind it. Rat mesenteric small arteries of different diameters (150–350 µm) were studied for noradrenaline-induced changes of isometric force and intracellular Ca2+ in smooth muscle cells. These functional changes were correlated to total Src kinase and Src phosphorylation assessed immunohistochemically. High-affinity ouabain-binding sites were semi-quantified with fluorescent ouabain. We found that potentiation of noradrenaline-sensitivity by ouabain correlates positively with an increase in arterial diameter. This was not due to differences in intracellular Ca2+ responses but due to sensitization of smooth muscle cell contractile machinery to Ca2+. This was associated with ouabain-induced Src activation, which increases with increasing arterial diameter. Total Src expression was similar in arteries of different diameters but the density of high-affinity ouabain binding sites increased with increasing arterial diameters. We suggested that ouabain binding induces more Src kinase activity in mesenteric small arteries with larger diameter leading to enhanced sensitization of the contractile machinery to Ca2+.

Airway smooth muscle tone modulates mechanically induced cytoskeletal stiffening and remodeling

2005 ◽  
Vol 99 (2) ◽  
pp. 634-641 ◽  
Author(s):  
Linhong Deng ◽  
Nigel J. Fairbank ◽  
Darren J. Cole ◽  
Jeffrey J. Fredberg ◽  
Geoffrey N. Maksym
Keyword(s):  
Smooth Muscle ◽  
Mechanical Stress ◽  
Applied Stress ◽  
Airway Smooth Muscle ◽  
Cell Activation ◽  
Structural Changes ◽  
Muscle Tone ◽  
Residual Effects ◽  
Cell Stiffness ◽  
Functional Changes

The application of mechanical stresses to the airway smooth muscle (ASM) cell causes time-dependent cytoskeletal stiffening and remodeling (Deng L, Fairbank NJ, Fabry B, Smith PG, and Maksym GN. Am J Physiol Cell Physiol 287: C440–C448, 2004). We investigated here the extent to which these behaviors are modulated by the state of cell activation (tone). Localized mechanical stress was applied to the ASM cell in culture via oscillating beads (4.5 μm) that were tightly bound to the actin cytoskeleton (CSK). Tone was reduced from baseline level using a panel of relaxant agonists (10−3 M dibutyryl cAMP, 10−4 M forskolin, or 10−6 M formoterol). To assess functional changes, we measured cell stiffness (G′) using optical magnetic twisting cytometry, and to assess structural changes of the CSK we measured actin accumulation in the neighborhood of the bead. Applied mechanical stress caused a twofold increase in G′ at 120 min. After cessation of applied stress, G′ diminished only 24 ± 6% (mean ± SE) at 1 h, leaving substantial residual effects that were largely irreversible. However, applied stress-induced stiffening could be prevented by ablation of tone. Ablation of tone also inhibited the amount of actin accumulation induced by applied mechanical stress ( P < 0.05). Thus the greater the contractile tone, the greater was applied stress-induced CSK stiffening and remodeling. As regards pathobiology of asthma, this suggests a maladaptive positive feedback in which tone potentiates ASM remodeling and stiffening that further increases stress and possibly leads to worsening airway function.

Myosin thick filament lability induced by mechanical strain in airway smooth muscle

2001 ◽  
Vol 90 (5) ◽  
pp. 1811-1816 ◽  
Author(s):  
Kuo-Hsing Kuo ◽  
Lu Wang ◽  
Peter D. Paré ◽  
Lincoln E. Ford ◽  
Chun Y. Seow
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Cross Sections ◽  
Structural Changes ◽  
Isometric Force ◽  
Mechanical Strain ◽  
Thick Filament ◽  
Functional Changes ◽  
Thick Filaments ◽  
Length Changes

Airway smooth muscle adapts to different lengths with functional changes that suggest plastic alterations in the filament lattice. To look for structural changes that might be associated with this plasticity, we studied the relationship between isometric force generation and myosin thick filament density in cell cross sections, measured by electron microscope, after length oscillations applied to the relaxed porcine trachealis muscle. Muscles were stimulated regularly for 12 s every 5 min. Between two stimulations, the muscles were submitted to repeated passive ±30% length changes. This caused tetanic force and thick-filament density to fall by 21 and 27%, respectively. However, in subsequent tetani, both force and filament density recovered to preoscillation levels. These findings indicate that thick filaments in airway smooth muscle are labile, depolymerization of the myosin filaments can be induced by mechanical strain, and repolymerization of the thick filaments underlies force recovery after the oscillation. This thick-filament lability would greatly facilitate plastic changes of lattice length and explain why airway smooth muscle is able to function over a large length range.

scholarly journals Water Loss during Contracture of Muscle

1962 ◽  
Vol 46 (1) ◽  
pp. 131-142 ◽  
Author(s):  
Benjamin Kaminer
Keyword(s):  
Smooth Muscle ◽  
Water Loss ◽  
Significant Loss ◽  
Frog Muscle ◽  
Tetanic Stimulation ◽  
Force Of Contraction ◽  
Freezing And Thawing ◽  
Microscopic Studies ◽  
Relationship Of ◽  
The Relationship

The relationship of contracture and exudation of water in frozenthawed frog muscle was studied. With maximum shortening, there was a water loss of 35 per cent of the weight of muscle. By restricting the contraction, it was demonstrated that the amount of water loss was proportional to the degree of shortening, there being no significant loss with isometric contraction. Muscle already shortened by tetanic stimulation also exuded water on subsequent freezing and thawing. The force of contraction could be reduced by depleting the muscle of calcium and it was shown that the amount of water exuded was also proportional to the tensile ability of the muscle. In a smooth muscle (anterior byssus retractor of Mytilus) which did not contract vigorously only a little water exuded. Contracture produced by caffeine was similarly associated with a loss of water. Microscopic studies revealed a disruption of the sarcomeres of the frozen-thawed muscle which contracted; glycerol-extracted and calcium-depleted muscles, which did not contract on freeze-thawing, did not show such disruption. Freezing and thawing of actomyosin caused a reversible syneresis of the protein. It is concluded that the exudation of the water is not merely due to the freezing and thawing but is also dependent on the contractile events.

scholarly journals Current status and advances in ram semen cryopreservation

2018 ◽  
Vol 69 (2) ◽  
pp. 911 ◽  
Author(s):  
A. NTEMKA ◽  
I. A. TSAKMAKIDIS ◽  
E. KIOSSIS ◽  
A. MILOVANOVIĆ ◽  
C. M. BOSCOS
Keyword(s):  
Artificial Insemination ◽  
Storage Temperature ◽  
Egg Yolk ◽  
Current Status ◽  
Freezing Process ◽  
Freezing And Thawing ◽  
Semen Cryopreservation ◽  
Functional Changes ◽  
Fertilizing Ability ◽  
Semen Preservation

Ram semen cryopreservation contributes to genetic improvement through artificial insemination, eliminates geographical barriers in artificial insemination application and supports the preservation of endangered breeds thus the conservation of biodiversity. Sperm freezing process induces ultrastructural, biochemical and functional changes of spermatozoa. Especially, spermatozoa’s membranes and chromatin can be damaged, sperm membranes’ permeability is increased, hyper oxidation and formation of reactive oxygen species takes place, affecting fertilizing ability and subsequent early embryonic development. Aiming to improve ram frozen-thawed semen’s fertilizing capacity, many scientific investigations took place. Among them the composition of semen extenders, was a main point of interest. Semen preservation extenders regulate and support an environment of adequate pH and buffering capacity to protect spermatozoa from osmotic and cryogenic stress. Therefore, permeating (glycerol, dimethyl sulfoxide) and non-permeat ing (egg yolk, skimmed milk) cryoprotectants, sugars (glucose, lactose, trehalose, raffinose), salts (sodium citrate, citric acid) and antioxidants (amino acids, vitamins, enzymes) have been added and tested. Moreover, semen dilution rate, storage temperature, cooling rate and thawing protocol, are also some key factors that have been studied. The research results of this scientific topic are encouraging, not only about the freezing and thawing procedures, but also about the improvement of the additives’ properties. However, further research is needed to enhance the fertilizing ability of ram frozen-thawed semen, making its use practical in sheep reproductive management by the application of cervical artificial insemination.

Abstract 312: Mechanisms Underlying Impaired KCl-induced Contractility After Long-term Serum-free Organ-culture of Rat Isolated Mesenteric Artery

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Tomoka Morita ◽  
Muneyoshi Okada ◽  
Hideyuki Yamawaki
Keyword(s):  
Smooth Muscle ◽  
Organ Culture ◽  
Mesenteric Artery ◽  
Cell Function ◽  
Mesenteric Arteries ◽  
Muscle Contractility ◽  
Smooth Muscle Contractility ◽  
Serum Free ◽  
Functional Changes

(Background and aim) Organ culture of blood vessels is a useful technique to investigate the long-term effects of drugs. Organ culture in a serum-free condition is so far the best way to maintain differentiated cell function. However some functional changes may occur from freshly isolated blood vessel (fresh) such as decreased contractility. Mammalian/mechanical target of rapamycin (mTOR) complex 1 is atypical serine/threonine kinase which integrates various signals induced by growth factors, stress, energy status, oxygen, and amino acids. Here, we investigated the mechanism of decrease in smooth muscle contractility after long-term serum-free organ culture specifically focusing on mTOR. (Methods and results) Rat isolated mesenteric arteries were cultured for 5 days without (0% serum) or with rapamycin (Rap). In 0% serum, absolute contraction by KCl significantly decreased from fresh (n=21 for fresh, n=7 for 0% serum, p<0.01 ). In Rap, the decreased contraction was significantly normalized (n=7, p<0.05 vs. 0% serum). In both 0% serum and Rap, sensitivity to KCl significantly increased from fresh ( p<0.01 vs. fresh). In 0% serum, mTOR expression significantly increased from fresh (n=8, p<0.01 ) which was significantly normalized by rapamycin (n=8, p<0.01 ). Morphological examinations showed degenerative changes in smooth muscle layer of 0% serum which was improved by rapamycin. In 0% serum, expression of myocardin, a master regulator of smooth muscle gene expression significantly decreased from fresh (n=9, p<0.01 ), which was significantly normalized by rapamycin (n=9, p<0.01 ). (Conclusion) Addition of rapamycin prevented the decreased contractility in serum-free organ cultured mesenteric artery perhaps by normalizing the mTOR and downstream myocardin expression as well as arterial degenerative morphological damage. Further studies are needed to clarify how mTOR controls myocardin expression and also how decreased myocardin expression leads to the decreased smooth muscle contractility. This experimental system may be useful for the hypertension research.

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