scholarly journals Ultrastructural and physiological studies on the longitudinal body wall muscle of Dolabella auricularia. I. Mechanical response and ultrastructure.

1978 ◽  
Vol 79 (2) ◽  
pp. 454-466 ◽  
Author(s):  
H Sugi ◽  
S Suzuki
Keyword(s):  
Body Wall ◽  
Mechanical Response ◽  
Body Movement ◽  
Smooth Muscles ◽  
Fiber Surface ◽  
Membrane Depolarization ◽  
Body Wall Muscle ◽  
Free Solution ◽  
Physiological Properties ◽  
Dolabella Auricularia

The physiological properties of mechanical response and the ultrastructure in the longitudinal body wall muscle (LBWM) of the opisthobranch mollusc Dolabella auricularia were studied to obtain information about excitation-contraction coupling in somatic smooth muscles responsible for smooth and slow body movement of molluscans. The contracture tension produced by 400 mM K was not affected by Mn ions (5--10 mM) and low pH (up to 4.0), but was reduced by procaine (2 mM). The K-contracture tension was not readily eliminated in a Ca-free solution containing ethylene glycol-bis(beta-aminoethyl ether)N,N,N',N'-tetraacetate (EGTA). A large contracture tension was also produced by rapid cooling of the surrounding fluid from 20 degrees to 5 degrees--3 degrees C even when the preparation showed no mechanical response to 400 mM K after prolonged (more than 2 h) soaking in the Ca-free solution. These results indicate that the LBWM fibers contain a large amount of intracellularly stored Ca which can be effectively released by membrane depolarization. The fibers were connected with each other, forming the gap junctions, the desmosomes, and the intermediate junctions. The sarcoplasmic reticulum (SR) consisted of vesicular and tubular elements, and was mostly located near the fiber surface. The plasma membrane showed marked tubular invaginations of 600-800 A in diameter, with many branches (surface tubules), extending inwards for approximately 2 micron. These surface tubules were closely apposed to the SR, and the bridgelike structures analogous to those in the triadic junction of vertebrate skeletal muscle were observed in the space between the surface tubules and the SR. It is suggested that the influence of membrane depolarization is transmitted inwards along the surface tubules to cause the release of Ca from the SR.

scholarly journals Ultrastructural and physiological studies on the longitudinal body wall muscle of Dolabella auricularia. II. Localization of intracellular calcium and its translocation during mechanical activity.

1978 ◽  
Vol 79 (2) ◽  
pp. 467-478 ◽  
Author(s):  
S Suzuki ◽  
H Sugi
Keyword(s):  
Plasma Membrane ◽  
Electron Probe ◽  
Body Wall ◽  
Mechanical Response ◽  
Body Wall Muscle ◽  
Mechanical Activity ◽  
Relaxation Cycle ◽  
X Ray ◽  
Dolabella Auricularia ◽  
Inner Surface

The localization of Ca-accumulating structures in the longitudinal body wall muscle (LBWM) of the opisthobranch mollusc Dolabella auricularia and their role in the contraction-relaxation cycle were studied by fixing the LBWM fibers at rest and during mechanical response to 400 mM K or to 10(-4)--10(-3) M acetylcholine in a 1% OsO4 solution containing 2% K pyroantimonate. In the resting fibers, electron-opaque pyroantimonate precipitate was mostly localized at the peripheral structures, i.e., along the inner surface of the plasma membrane, at the membrane of the surface tubules, and at the sarcoplasmic reticulum. In the fibers fixed during mechanical activity, the precipitate was diffusely distributed in the myoplasm in the form of numerous particles with corresponding decrease in the amount of the precipitate at the peripheral structures. Electron-probe X-ray microanalysis showed the presence of Ca in the precipitate, indicating that the precipitate may serve as a measure of Ca localization. These results are in accord with the view that, in the LBWM, the Ca stored in the peripheral structures is released into the myoplasm to activate the contractile mechanism.

Physiological and Ultrastructural Studies on the Longitudinal Retractor Muscle of a Sea Cucumber Stichopus Japonicus: I. Factors Influencing the Mechanical Response

1982 ◽  
Vol 97 (1) ◽  
pp. 101-111
Author(s):  
H. SUGI ◽  
S. SUZUKI ◽  
T. TSUCHIYA ◽  
S. GOMI ◽  
N. FUJIEDA
Keyword(s):  
Plasma Membrane ◽  
Sea Cucumber ◽  
Mechanical Response ◽  
Divalent Cations ◽  
Smooth Muscles ◽  
Retractor Muscle ◽  
Stichopus Japonicus ◽  
Ultrastructural Studies ◽  
Physiological Properties ◽  
After Effect

1. The physiological properties of contraction and the ultrastructure of the longitudinal retractor muscle (LRM) of a sea cucumber Stichopus japonicus were studied to give information about the sources of activator Ca in echinoderm somatic smooth muscles. 2. The magnitude of ACh- and K-induced contractures was dependent on [Ca]0, and both contractures were eliminated in Ca-free solution, while they were not markedly influenced by Mn ions (10 mM) and low pH (4.0). 3. Procaine (5 mM) decreased ACh-contracture tension with a long lasting after-effect, which was removed by the application of high [K]0. 4. ACh-contractures were markedly potentiated shortly after the termination of mechanical response to the removal of external Na. 5. The LRM could also be made to contract by caffeine (10 mM), the removal of external divalent cations and hypertonic solutions, indicating the presence of intracellularly stored Ca available for the activation of the contractile mechanism. 6. The LRM fibres contain poorly developed intracellular membranous structures. The inner surface of the plasma membrane and small vesicles located underneath the plasma membrane seem to be two of the sources of activator Ca.

scholarly journals The L-type voltage-dependent Ca2+ channel EGL-19 controls body wall muscle function in Caenorhabditis elegans

2002 ◽  
Vol 159 (2) ◽  
pp. 337-348 ◽  
Author(s):  
Maëlle Jospin ◽  
Vincent Jacquemond ◽  
Marie-Christine Mariol ◽  
Laurent Ségalat ◽  
Bruno Allard
Keyword(s):  
Caenorhabditis Elegans ◽  
Body Wall ◽  
Muscle Cells ◽  
Membrane Depolarization ◽  
Cellular Level ◽  
Body Wall Muscle ◽  
K Channel ◽  
Channel Blockers ◽  
Patch Clamp Technique ◽  
Voltage Dependent

Caenorhabditis elegans is a powerful model system widely used to investigate the relationships between genes and complex behaviors like locomotion. However, physiological studies at the cellular level have been restricted by the difficulty to dissect this microscopic animal. Thus, little is known about the properties of body wall muscle cells used for locomotion. Using in situ patch clamp technique, we show that body wall muscle cells generate spontaneous spike potentials and develop graded action potentials in response to injection of positive current of increasing amplitude. In the presence of K+ channel blockers, membrane depolarization elicited Ca2+ currents inhibited by nifedipine and exhibiting Ca2+-dependent inactivation. Our results give evidence that the Ca2+ channel involved belongs to the L-type class and corresponds to EGL-19, a putative Ca2+ channel originally thought to be a member of this class on the basis of genomic data. Using Ca2+ fluorescence imaging on patch-clamped muscle cells, we demonstrate that the Ca2+ transients elicited by membrane depolarization are under the control of Ca2+ entry through L-type Ca2+ channels. In reduction of function egl-19 mutant muscle cells, Ca2+ currents displayed slower activation kinetics and provided a significantly smaller Ca2+ entry, whereas the threshold for Ca2+ transients was shifted toward positive membrane potentials.

Ectopic Germ Cells Can Induce Niche-Like Enwrapment by Neighboring Body Wall Muscle

2018 ◽  
Author(s):  
Kacy L. Gordon ◽  
Sara G. Payne ◽  
Lara M. Linden-High ◽  
Ariel M. Pani ◽  
Bob Goldstein ◽  
...  
Keyword(s):  
Germ Cells ◽  
Body Wall ◽  
Body Wall Muscle

scholarly journals A screen for genetic loci required for body-wall muscle development during embryogenesis in Caenorhabditis elegans.

Genetics ◽  
1994 ◽  
Vol 137 (2) ◽  
pp. 483-498
Author(s):  
J Ahnn ◽  
A Fire
Keyword(s):  
Caenorhabditis Elegans ◽  
Myosin Heavy Chain ◽  
Muscle Cell ◽  
Heavy Chain ◽  
Body Wall ◽  
Muscle Development ◽  
Contractile Function ◽  
The Body ◽  
Body Wall Muscle ◽  
Genetic Loci

Abstract We have used available chromosomal deficiencies to screen for genetic loci whose zygotic expression is required for formation of body-wall muscle cells during embryogenesis in Caenorhabditis elegans. To test for muscle cell differentiation we have assayed for both contractile function and the expression of muscle-specific structural proteins. Monoclonal antibodies directed against two myosin heavy chain isoforms, the products of the unc-54 and myo-3 genes, were used to detect body-wall muscle differentiation. We have screened 77 deficiencies, covering approximately 72% of the genome. Deficiency homozygotes in most cases stain with antibodies to the body-wall muscle myosins and in many cases muscle contractile function is observed. We have identified two regions showing distinct defects in myosin heavy chain gene expression. Embryos homozygous for deficiencies removing the left tip of chromosome V fail to accumulate the myo-3 and unc-54 products, but express antigens characteristic of hypodermal, pharyngeal and neural development. Embryos lacking a large region on chromosome III accumulate the unc-54 product but not the myo-3 product. We conclude that there exist only a small number of loci whose zygotic expression is uniquely required for adoption of a muscle cell fate.

Physiological Properties of Late Inspiratory Neurons and Their Possible Involvement in Inspiratory Off-Switching in Cats

2002 ◽  
Vol 87 (2) ◽  
pp. 1057-1067 ◽  
Author(s):  
Akira Haji ◽  
Mari Okazaki ◽  
Hiromi Yamazaki ◽  
Ryuji Takeda
Keyword(s):  
Nmda Receptors ◽  
Gaba Release ◽  
Membrane Depolarization ◽  
Inhibitory Neurons ◽  
Acid Decarboxylase ◽  
Postsynaptic Potentials ◽  
Inspiratory Neurons ◽  
Small Constant ◽  
Physiological Properties ◽  
Decerebrate Cats

To assess the functional significance of late inspiratory (late-I) neurons in inspiratory off-switching (IOS), membrane potential and discharge properties were examined in vagotomized, decerebrate cats. During spontaneous IOS, late-I neurons displayed large membrane depolarization and associated discharge of action potentials that started in late inspiration, peaked at the end of inspiration, and ended during postinspiration. Depolarization was decreased by iontophoresis of dizocilpine and eliminated by tetrodotoxin. Stimulation of the vagus nerve or the nucleus parabrachialis medialis (NPBM) also evoked depolarization of late-I neurons and IOS. Waves of spontaneous chloride-dependent inhibitory postsynaptic potentials (IPSPs) preceded membrane depolarization during early inspiration and followed during postinspiration and stage 2 expiration of the respiratory cycle. Iontophoresed bicuculline depressed the IPSPs. Intravenous dizocilpine caused a greatly prolonged inspiratory discharge of the phrenic nerve (apneusis) and suppressed late-inspiratory depolarization as well as early-inspiratory IPSPs, resulting in a small constant depolarization throughout the apneusis. NPBM or vagal stimulation after dizocilpine produced small, stimulus-locked excitatory postsynaptic potentials (EPSPs) in late-I neurons. Neurobiotin-labeled late-I neurons revealed immunoreactivity for glutamic acid decarboxylase as well as N-methyl-d-aspartate (NMDA) receptors. These results suggest that late-I neurons are GABAergic inhibitory neurons, while the effects of bicuculline and dizocilpine indicate that they receive periodic waves of GABAergic IPSPs and glutamatergic EPSPs. The data lead to the conclusion that late-I neurons play an important inhibitory role in IOS. NMDA receptors are assumed to augment and/or synchronize late-inspiratory depolarization and discharge of late-I neurons, leading to GABA release and consequently off-switching of bulbar inspiratory neurons and phrenic motoneurons.

Duels without obvious sense: counteracting inductions involved in body wall muscle development in the Caenorhabditis elegans embryo

Development ◽  
1995 ◽  
Vol 121 (7) ◽  
pp. 2219-2232 ◽  
Author(s):  
R. Schnabel
Keyword(s):  
Caenorhabditis Elegans ◽  
Body Wall ◽  
Muscle Development ◽  
Early Embryo ◽  
Cell Interactions ◽  
Body Wall Muscle ◽  
Cellular Interactions ◽  
Classical Criterion ◽  
Founder Cells ◽  
Cell Cell

During the first four cleavage rounds of the Caenorhabditis elegans embryo, five somatic founder cells AB, MS, E, C and D are born, which later form the tissues of the embryo. The classical criterion for a cell-autonomous specification of a tissue is the capability of primordial cells to produce this tissue in isolation from the remainder of the embryo. By this criterion, the somatic founder cells MS, C and D develop cell-autonomously. Laser ablation experiments, however, reveal that within the embryonic context these blastomeres form a network of duelling cellular interactions. During normal development, the blastomere D inhibits muscle specification in the MS and the C lineage inhibits muscle specification in the D lineage. These inhibitory interactions are counteracted by two activating inductions. As described before the inhibition of body wall muscle in MS is counteracted by an activating signal from the ABa lineage. Body wall muscle in the D lineage is induced by MS descendants, which suppress an inhibitory activity of the C lineage. The interaction between the D and the MS lineage occurs through the C lineage. An interesting feature of these cell-cell interactions is that they do not serve to discriminate between equivalent cells but are permissive or nonpermissive inductions. No evidence was found that the C-derived body wall muscle also depends on an induction, which suggests that possibly three different pathways coexist in the early embryo to specify body wall muscle, two of which are, in different ways, influenced by cell-cell interactions and a third that is autonomous. This work supplies evidence that cells may acquire transient states during embryogenesis that influence the specification of other cells in the embryo. These states, however, may not be reflected in the developmental potentials of the cells themselves. They can only be scored indirectly by their action on the specification of other cells in the embryo. Blastomeres that behave cell-autonomously in isolation are nevertheless subjected to cell-cell interactions in the embryonic context. Why this should be is an intriguing question. The classical notion has been that blastomeres are specified autonomously in nematodes. In recent years, it was established that at least five inductions are required to determine the AB descendants of C. elegans, whereas the P1 descendants have been typically viewed to develop more autonomously. It appears now that inductions also play a major role during the determination of P1-derived blastomeres.

scholarly journals Ca^-binding to site IV and TnI-binding of body-wall muscle troponin C are essential for development in Caenorhabditis elegans

2004 ◽  
Vol 44 (supplement) ◽  
pp. S65
Author(s):  
T. Takaya ◽  
H. Terami ◽  
M. Sohda ◽  
T. Iio ◽  
H. Kagawa
Keyword(s):  
Caenorhabditis Elegans ◽  
Body Wall ◽  
Troponin C ◽  
Body Wall Muscle
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