scholarly journals The regulation of tension in a chemically skinned molluscan smooth muscle: effect of Mg2+ on the Ca2+-activated tension generation.

1980 ◽  
Vol 75 (6) ◽  
pp. 709-725 ◽  
Author(s):  
F Cornelius
Keyword(s):  
Active State ◽  
Retractor Muscle ◽  
Striated Muscles ◽  
Free Concentration ◽  
Tension Development ◽  
Maximum Tension ◽  
Tension Level ◽  
Catch State ◽  
Complicated Model ◽  
Triton X

Chemically skinned anterior byssus retractor muscle (ABRM) preparations were prepared by treatment with the nonionic detergents saponin and Triton X-100. Both maximum peak tension and rate of contraction were found to be greater in saponin-treated ABRM than in ABRM treated with Triton X-100. Active tension was initiated at a concentration of free Ca2+ above 0.1 microM, and maximum tension development was found at a [Ca2+] = approximately 32 microM. During exposure of the muscle preparation to optimal Ca2+ concentration, a high and almost constant tension level was sustained. The force recovery was high after a quick release during this period indicating the presence of an "active" state rather than a "catch" state. Actually, a state equivalent to the catch state in the living ABRM could not be induced, if the Ca2+ concentration was above 0.1 microM. Variations in the ionic strength in the range of 0.07--0.28 M had no influence on active state and only slightly affected the maximum tension developed. The influence of Mg2+ on the Ca2+-activated tension was examined by studying the tension-pCa relation at two concentrations of free Mg2+ (0.43 and 4.0 mM). The tension-pCa relation was found to be S-shaped with tension increasing steeply over approximately 1 pCa unit, indicating the existence of cooperativity between Ca2+ sites. Increasing the free concentration of Mg2+ shifted the tension-pCa relation to lower pCa as in striated muscles, demonstrating a decreasing Ca2+ sensitivity with increasing Mg2+. At [Mg2+] = 4.0 mM the half-maximum tension was found at [Ca2+] = 0.43 microM, decreasing to 0.20 microM at [Mg2+] = 0.43 mM. At both Mg2+ concentrations studied, plots of log Prel/(1--Prel) vs. log [Ca2+] were nonlinear with a shape indicating a rather complicated model for cooperativity, probably involving four sites for Ca2+. These Ca2+--Mg2+ interactions are most probably taking place at the myosin head itself because troponin is absent in this myosin-regulated muscle.

scholarly journals Tonic contraction and the control of relaxation in a chemically skinned molluscan smooth muscle.

1982 ◽  
Vol 79 (5) ◽  
pp. 821-834 ◽  
Author(s):  
F Cornelius
Keyword(s):  
Muscle Length ◽  
Tonic Contraction ◽  
Active State ◽  
Retractor Muscle ◽  
Muscle Preparation ◽  
Tension Development ◽  
Maximum Tension ◽  
Skinned Muscle ◽  
Catch State ◽  
Molluscan Smooth Muscle

The same functional states that characterize the living anterior byssus retractor muscle (ABRM) from Mytilus edulis can be initiated in the saponin-treated (chemically skinned) muscle preparation under controlled biochemical conditions. A tonic contraction was induced if the concentration of free Ca2+ was above approximately 10(7) M in the presence of Mg2+ and ATP. Maximum tension development was achieved at a Ca2+ concentration of approximately 10(4) M. Within these Ca2+ concentrations tension was always associated with the presence of 'active state," as indicated by a high recovery of tension after a quick release in muscle length. Tonic tension, and the associated active state was maintained for hours during these conditions irrespective of variations in both ionic strength and pH. Reduction of the Ca2+ concentration to below threshold for tension initiation during a tonic contraction immediately switched off the active state and relaxation of the muscle preparation resulted. However, the rate of relaxation was extremely low, leaving a substantial fraction of tension in the absence of active state. Both 5-hydroxytryptamine (5-HT) and cAMP accelerated this slow relaxation in the absence of Ca2+. Thus, this state was considered equivalent to the 'catch state" in the living ABRM. In the presence of Ca2+ concentrations above 10(7) M, cAMP did not affect either the maximum tension developed or the Ca2+ sensitivity of the chemically skinned muscle preparation.

Active state plateau and latency in mammalian striated muscle

1961 ◽  
Vol 200 (4) ◽  
pp. 667-671 ◽  
Author(s):  
Forbes H. Norris
Keyword(s):  
Latent Period ◽  
Striated Muscle ◽  
Muscle Length ◽  
Single Stimulus ◽  
Active State ◽  
Tension Development ◽  
Maximum Tension ◽  
Tension Curves ◽  
Tetanic Tension

The active state plateau in rat striated muscle was studied by superimposition of tension curves resulting from one and two stimuli. The plateau ends 4.0 ± 0.1 msec. after stimulation in rat striated muscle at 36°C. The time to the end of the plateau is 3.4 ± 0.1 times the latent period. During the plateau, response to a second stimulus appears after increased mechanical latency. The second stimulus can also result in tension development at rates nearly twice those reached after a single stimulus. This effect has a peak which about corresponds to the end of the active state plateau, but precedes the peak of the curve for maximum tension. Correct timing of the second stimulus can result in about 60% of tetanic tension. The use of thiopental, gallamine, tubocurarine and changes in muscle length did not affect these results.

The effect of temperature on the tension responses of the anterior byssal retractor muscle (abrm) of Mytilus edulis

1982 ◽  
Vol 97 (1) ◽  
pp. 375-384
Author(s):  
C. M. Linehan
Keyword(s):  
Ambient Temperature ◽  
Latent Period ◽  
Mytilus Edulis ◽  
Effect Of Temperature ◽  
Retractor Muscle ◽  
Tension Development ◽  
Maximum Tension ◽  
Peak Tension ◽  
The Relationship ◽  
Anterior Byssal Retractor Muscle

The effect of ambient temperature on the response of the ABRM of Mytilus edulis to acetylcholine and 5-hydroxytryptamine has been examined. As the ambient temperature was increased, the latent period and the maximum tension developed decreased while the rate of tension development and the rate of relaxation increased. The relationship between temperature and the rate of tension development showed three distinct linear phases from 2–25, 25-35 and 35-45 degrees C. The reduction in peak tension with temperature could also be resolved into three portions from 2–25, 25-40 and above 40 degrees C. As the temperature was increased above approximately 27 degrees C the rate of relaxation in the absence of 5-HT approached the rate of relaxation in the presence of 5-HT. The significance of these results and possible explanations for them are considered.

scholarly journals The effect of altered temperature on Ca2(+)-sensitive force in permeabilized myocardium and skeletal muscle. Evidence for force dependence of thin filament activation.

1990 ◽  
Vol 96 (6) ◽  
pp. 1221-1245 ◽  
Author(s):  
N K Sweitzer ◽  
R L Moss
Keyword(s):  
Skeletal Muscle ◽  
Cardiac Muscle ◽  
Thin Filament ◽  
Calcium Sensitivity ◽  
Differential Sensitivity ◽  
Fiber Types ◽  
Tension Development ◽  
Maximum Tension ◽  
Filament Activation ◽  
Muscle Types

The effect of changes in temperature on the calcium sensitivity of tension development was examined in permeabilized cellular preparations of rat ventricle and rabbit psoas muscle. Maximum force and Ca2+ sensitivity of force development increased with temperature in both muscle types. Cardiac muscle was more sensitive to changes in temperature than skeletal muscle in the range 10-15 degrees C. It was postulated that the level of thin filament activation may be decreased by cooling. To investigate this possibility, troponin C (TnC) was partially extracted from both muscle types, thus decreasing the level of thin filament activation independent of temperature and, at least in skeletal muscle fibers, decreasing cooperative activation of the thin filament as well. TnC extraction from cardiac muscle reduced the calcium sensitivity of tension less than did extraction of TnC from skeletal muscle. In skeletal muscle the midpoint shift of the tension-pCa curve with altered temperature was greater after TnC extraction than in control fibers. Calcium sensitivity of tension development was proportional to the maximum tension generated in cardiac or skeletal muscle under all conditions studied. Based on these results, we conclude that (a) maximum tension-generating capability and calcium sensitivity of tension development are related, perhaps causally, in fast skeletal and cardiac muscles, and (b) thin filament activation is less cooperative in cardiac muscle than in skeletal muscle, which explains the differential sensitivity of the two fiber types to temperature and TnC extraction. Reducing thin filament cooperativity in skeletal muscle by TnC extraction results in a response to temperature similar to that of control cardiac cells. This study provides evidence that force levels in striated muscle influence the calcium binding affinity of TnC.

scholarly journals Morfologi Hemipenis Biawak Air (Varanus salvator bivittatus)

2017 ◽  
Vol 35 (1) ◽  
pp. 111
Author(s):  
Mahfud Mahfud ◽  
Adi Winarto ◽  
Chairun Nisa
Keyword(s):  
Connective Tissue ◽  
Blood Vessels ◽  
Copulatory Organ ◽  
Retractor Muscle ◽  
Striated Muscles ◽  
Section Thickness ◽  
Microscopic Anatomy ◽  
Varanus Salvator ◽  
Hematoxylin Eosin ◽  
Cavernous Body

Varanus salvator bivittatus has a pair of hemipenes, which is macroscopic anatomically like the copulatory organ in other amniotes, cylindrical-shaped (truncus) with quite flexible, and it located on the base of the caudal tailof the cloaca. However, information about the microscopic anatomy of hemipenes of this animal is scientifically unpublicized. Therefore, the aim of this research is to study the microscopic anatomy of hemipenes of male Varanussalvator bivittatus. The animals were sacrificed by exsanguination under deep anesthetized and fixed in 4 % paraformaldehyde through perfusion then observed visceral site and morphometric. Histomorphological evaluationwas obtained by paraffin preparation with section thickness of 3-4 μm then stained in Hematoxylin-Eosin (HE) and Masson’s Trichrome (MT). The results showed that truncus of hemipenes was lined by stratified squamousepithelium and supported with thick of dense connective tissue and contain cavernous body and blood vessels are found, the muscles not found. The presence of connective tissue that supported in the down part sometimesmake hemipenes are rigid while prurient condition. In the caudal of truncus hemipenes there is retractor muscle of hemipenes which arranged by striated muscles. Hemipenes is flexible because contain with much of blood vesselthat found in truncus hemipenes.

scholarly journals Mechanism and Function of the Catch State in Molluscan Smooth Muscle: A Historical Perspective

2020 ◽  
Vol 21 (20) ◽  
pp. 7576
Author(s):  
Haruo Sugi ◽  
Tetsuo Ohno ◽  
Masamichi Moriya
Keyword(s):  
Smooth Muscles ◽  
Ion Concentration ◽  
Retractor Muscle ◽  
Electron Microscopic ◽  
Isotonic Condition ◽  
Catch State ◽  
Ca Ions ◽  
Molluscan Smooth Muscle ◽  
And Function ◽  
Intracellular Translocation

Molluscan smooth muscles exhibit the catch state, in which both tension and resistance to stretch are maintained with very low rates of energy consumption. The catch state is studied mainly on the anterior byssus retractor muscle (ABRM) of a bivalve molluscan animal, Mytilus, which can easily be split into small bundles consisting of parallel fibers. The ABRM contracts actively with an increase in the intracellular free Ca ion concentration, [Ca2+]i, as with all other types of muscle. Meanwhile, the catch state is established after the reduction of [Ca2+]i to the resting level. Despite extensive studies, the mechanism underlying the catch state is not yet fully understood. This article briefly deals with (1) anatomical and ultrastructural aspects of the ABRM, (2) mechanical studies on the transition from the active to the catch state in the isotonic condition, (3) electron microscopic and histochemical studies on the intracellular translocation of Ca ions during the transition from the active to the catch state, and (4) biochemical studies on the catch state, with special reference to a high molecular mass protein, twitchin, which is known to occur in molluscan catch muscles.

scholarly journals Carbonic anhydrase in skeletal and cardiac muscle from rabbit and rat

1992 ◽  
Vol 282 (1) ◽  
pp. 165-171 ◽  
Author(s):  
C Geers ◽  
D Krüger ◽  
W Siffert ◽  
A Schmid ◽  
W Bruns ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Cardiac Muscle ◽  
High Activity ◽  
Skeletal Muscles ◽  
Carbonic Anhydrases ◽  
Striated Muscles ◽  
Membrane Bound ◽  
Triton X ◽  
Dextran Solution ◽  
Low Activity

We have studied the distribution of carbonic anhydrases (CA) in several skeletal muscles of the hindlimb of rabbits and rats and in cardiac muscle of the rabbit. To remove erythrocyte CA, hindlimbs and hearts were thoroughly perfused with dextran solution, and the effectiveness of the perfusion was in most cases assessed by determining the contamination of the muscles with radioisotopes that had been used to label the erythrocytes before the perfusion was started. We observed three forms of CA: (1) cytosolic (sulphonamide-resistant) CA III; (2) a cytosolic sulphonamide-sensitive CA, probably isoenzyme II; (3) a membrane-bound form that was extracted from the particulate fraction using Triton X-100. These CA isoforms were distributed as follows. (1) CA III is located in the cytoplasm of slow, oxidative skeletal muscles and is absent from or low in fast skeletal and cardiac muscle; this holds for rabbits and rats and is identical with the pattern previously described for several other species. (2) The cytosolic sulphonamide-sensitive CA is present in fast rabbit muscles and absent from slow muscles of this species. In contrast, all skeletal muscles of the rat studied here lack, or possess only very low, activity of this isoenzyme. (3) The membrane-bound form of CA is present in all rabbit muscles studied; its activity appears somewhat higher in fast than in slow skeletal muscles. (4) Cardiac muscle constitutes an exception among all striated muscles of the rabbit as it possesses no form of cytosolic CA but a high activity of the membrane-bound form.

Contractile Responses of Canine Isolated Pulmonary Lobar Arteries and Veins to Norepinephrine, Serotonin, and Tyramine

1975 ◽  
Vol 53 (5) ◽  
pp. 830-838 ◽  
Author(s):  
Paul D. Joiner ◽  
Philip J. Kadowitz ◽  
Linda B. Davis ◽  
Albert L. Hyman
Keyword(s):  
Adrenergic Receptors ◽  
Adrenergic Nerve ◽  
Nerve Terminals ◽  
Tension Development ◽  
Consistent Effect ◽  
Maximum Tension ◽  
Adrenergic Blocker ◽  
Adrenergic Nerve Terminals ◽  
High Concentrations ◽  
Arteries And Veins

Isolated helical strips of canine intrapulmonary lobar arteries and veins (about 4 mm in diameter) undergo dose-related tension development when exposed to increasing concentrations (10−8 – 10−3 M) of norepinephrine (NE), serotonin or 5-hydroxytryptamine (5-HT) and tyramine (Tyr). Venous segments were generally more sensitive while the maximum tension development was greater in the arterial strips, probably owing to their greater thickness. Both strips were more sensitive to 5-HT than NE and only responded to Tyr at high concentrations. Norepinephrine and 5-HT were nearly equally efficacious, whereas Tyr was less so. Responses to the latter were slow to develop, exhibited tachyphylaxis, and were greatly inhibited by phentolamine (10−8 M), an α-adrenergic blocker. Exposure to cocaine (10−5 M) enhanced submaximal NE responses, inhibited Tyr contractions and had no consistent effect on 5-HT responses. Phentolamine (10−8 M) was also found to inhibit NE responses without altering 5-HT effects, whereas methysergide (10−8 M) inhibited 5-HT responses but not NE contractions. Thus, evidence suggests that NE probably acts on α-adrenergic receptors whereas 5-HT probably acts on other receptors. Tyramine may, in part, act directly on α-adrenergic receptors but may also release NE from surviving adrenergic nerve terminals in the preparation. Cocaine inhibits this effect and potentiates responses to lower levels of NE, presumably by blocking NE uptake into nerve terminals although a post-junctional action cannot be excluded.

scholarly journals The Effects of Temperature upon Contraction and Ionic Exchange in Rabbit Ventricular Myocardium

1968 ◽  
Vol 52 (4) ◽  
pp. 682-713 ◽  
Author(s):  
G. A. Langer ◽  
A. J. Brady
Keyword(s):  
Ventricular Myocardium ◽  
Isometric Tension ◽  
Active State ◽  
Ionic Exchange ◽  
Active Tension ◽  
Tension Development ◽  
Mechanical Responses ◽  
Abrupt Changes ◽  
Rabbit Ventricular Myocardium ◽  
Temperature Rate

The mechanical responses (active and resting tension, dP/dt, TPT) and ionic exchange characteristics (Ca++, K+, Na+) which follow upon a variation in temperature, rate, and [K+]0 were studied in the rabbit papillary muscle and arterially perfused rabbit interventricular setpum. Abrupt changes in temperature provided a means of separating the contributions of rate of development (intensity) of active state and duration of active state to total active tension development (approximated by isometric tension). Threefold changes in duration of active state with proportional changes in active tension can be induced without evidence for alteration of Ca++, K+, or Na+ exchange. Abrupt cooling produced a moderate (∼15%) increase of dP/dt which suggests an augmentation of active state intensity. Evidence is presented to suggest that this increase of dP/dt is based upon an increase in membrane Ca++ concentration which occurs secondary to inhibition of active Na+ transport. The alterations in ionic exchange and active state produced by variation of temperature are discussed in terms of a five-component control system.

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