The Mechanical Properties of the Longitudinal Muscle in the Earthworm

1969 ◽  
Vol 50 (2) ◽  
pp. 431-443 ◽  
Author(s):  
T. HIDAKA ◽  
H. KURIYAMA ◽  
T. YAMAMOTO
Keyword(s):  
Mechanical Properties ◽  
Longitudinal Muscle ◽  
Sodium Concentration ◽  
Membrane Resistance ◽  
Membrane Properties ◽  
Active Tension ◽  
Spike Generation ◽  
Tension Development ◽  
Sustained Contraction ◽  
Intracellular Stimulation

1. A study of the mechanical properties of longitudinal muscle in relation to the membrane properties was carried out under isometric conditions. 2. When the stimulus duration exceeded 50 msec., active tension development was followed by sustained contraction. The sustained contractions were not related to spike generation. 3. The critical potassium concentration to produce the contracture depolarized the membrane from -36 to -20 mV. 4. Reduced sodium concentration and increased calcium and increased potassium (up to 27 mM) concentrations enhanced the amplitude of the active tension. 5. Reduced sodium concentration enhanced the amplitude and duration of the sustained tension, but increased potassium and calcium concentrations reduced them. 6. Caffeine (12 mM) induced contractures of the muscle, and reduced the membrane resistance and capacitance. 7. Spikes were not elicited by intracellular stimulation. 8. 5-Hydroxytryptamine (10-5 g./ml.) blocked the generation of the sustained contraction but no effect was observed on the phasic tension.

Mechanical Properties of the Longitudinal and Circular Muscle in the Earthworm

1971 ◽  
Vol 55 (1) ◽  
pp. 101-110
Author(s):  
N. TASHIRO
Keyword(s):  
Mechanical Properties ◽  
Longitudinal Muscle ◽  
Circular Muscle ◽  
Tonic Contraction ◽  
Muscle Fibres ◽  
Field Stimulation ◽  
Free Solution ◽  
Tension Development ◽  
Phasic Contraction

1. The mechanical properties of the longitudinal and circular muscles of the earthworm, Pheretima communissima, were studied in various solutions. 2. In the longitudinal muscle, field stimulation elicited two distinct waves of tension development, i.e. phasic and tonic contractions. But in the circular muscle, these components were not distinguishable. 3. The phasic contraction in the longitudinal muscle increased in sodium-free (tris) solution while the tonic contraction was abolished. Neither the phasic nor the tonic contraction, however, was influenced by tetrodotoxin (3 x 10-6 M), d-tubocurarine (1.4 x 10-5M), or atropine (3.5 x 10-5 M). 4. The contraction in the circular muscle was suppressed in sodium-free solution and also by tetrodotoxin (3 x 10-6 M), but was not affected by d-tubocurarine (1.4 x 10-5 M) or by atropine (3.5 x 10-5M). 5. It is speculated that the phasic contraction of the longitudinal muscle is triggered by a calcium spike, and the contraction in the circular muscle is preceded by a sodium spike in muscle fibres.

Neuropeptide responses and mechanics of the proximal and distal feline colon in vitro

1988 ◽  
Vol 255 (6) ◽  
pp. G787-G793
Author(s):  
A. Merlo ◽  
S. Cohen
Keyword(s):  
Mechanical Properties ◽  
Substance P ◽  
Longitudinal Muscle ◽  
Circular Muscle ◽  
Isometric Contractions ◽  
Active Tension ◽  
Intrinsic Properties ◽  
Cholecystokinin Octapeptide ◽  
Anatomic Region

Mechanical properties and responses to neuropeptides were compared for proximal and distal feline colonic muscle. Proximal longitudinal (PL), proximal circular (PC), distal longitudinal (DL), and distal circular (DC) muscles were studied in vitro under isometric conditions. Total tension in DL [1.636 +/- 0.009 (SE) kg/cm2] was greater than in DC (0.699 +/- 0.004 kg/cm2) or PC (0.710 +/- 0.005 kg/cm2, P less than 0.05). Longitudinal muscle developed proportionately more active tension than circular muscle at each region (80.9% in DL vs. 54.1% in DC and 77.1% in PL vs. 52.3% in PC, P less than 0.01). Neuropeptides varied in potency and efficacy. Cholecystokinin octapeptide (CCK-8) was the most potent and efficacious in PL and substance P was the most efficacious in PC muscle (P less than 0.05). Substance P was more efficacious whereas CCK-8 and neurotensin were less efficacious in PC than PL muscle (P less than 0.01). DL muscle did not respond to CCK-8. DC muscle did not respond to CCK-8 or neurotensin. Isometric contractions to each neuropeptide were insensitive to tetrodotoxin. We conclude that 1) mechanical properties of circular and longitudinal colonic muscle differ and 2) responses to neuropeptides depend on anatomic region and intrinsic properties.

scholarly journals Membrane Properties of the Somatic Muscle (Obliquely Striated Muscle) of the Earthworm

1969 ◽  
Vol 50 (2) ◽  
pp. 387-403
Author(s):  
T. HIDAKA ◽  
Y. ITO ◽  
H. KURIYAMA
Keyword(s):  
Membrane Potential ◽  
Muscle Fibre ◽  
Striated Muscle ◽  
Longitudinal Muscle ◽  
Nervous Activity ◽  
Membrane Properties ◽  
Somatic Muscle ◽  
Intracellular Stimulation ◽  
Longitudinal Muscles ◽  
Spontaneous Discharges

1. The membrane properties of the longitudinal muscle fibre of the earthworm Pheretima communissima were investigated by intra- and extracellular stimulating methods. 2. The membrane potential was -35.4 mV., and spontaneous discharges with overshoot (mean +18 mV.) and after-hyperpolarization (-60 mV.) were recorded. 3. Tetrodotoxin (10-7 g./ml.) blocked nervous activity but did not influence the spontaneous discharges or the spikes elicited in the muscle fibre by intracellular stimulation. 4. The critical membrane potential required to elicit a spike was not constant, and the falling phase of the spikes was markedly dependent on the level of the membrane potential. 5. The chronaxie, measured from the intensity-duration relation to elicit a spike by intracellular stimulation, was 55 msec. 6. When nervous activity was excluded the propagation of excitation in longitudinal muscles was decremental.

Temporal changes in mechanical properties of rat jejunal smooth muscle after myenteric plexus ablation

1987 ◽  
Vol 253 (6) ◽  
pp. G745-G750
Author(s):  
J. R. Herman ◽  
P. Bass
Keyword(s):  
Smooth Muscle ◽  
Myenteric Plexus ◽  
Longitudinal Muscle ◽  
Contractile Activity ◽  
Circular Muscle ◽  
Stress Generation ◽  
Active Tension ◽  
Tension Development ◽  
Tension Generation ◽  
Muscle Responses

We determined length-stress properties and active tension development of rat jejunal longitudinal and circular muscle at various times after myenteric neuron ablation. Myenteric neurons were destroyed by serosal application of benzalkonium chloride. Active tension generation in response to both carbachol and barium was depressed in both muscle layers up to 7 days after treatment, at which times the responses were normal. At 15 days, circular muscle responses were still comparable to control, but longitudinal muscle responses were significantly increased. Length-stress parameters of circular muscle were minimally affected, while those of longitudinal muscle were significantly altered 15 and 30 days after treatment. These alterations include changes in resting stress and increased active stress generation at both times. Our results suggest that 1) normal myenteric innervation is necessary for normal contractile activity in rat jejunal smooth muscle and 2) changes in cellular or tissue morphology or alterations in intracellular calcium homeostasis, as seen in other tissue, may occur after myenteric plexus ablation.

Calcium Spike in the Longitudinal Muscle of the Lobworm, Tylorrynchus Heterochaetus, (Nereidae)

1970 ◽  
Vol 53 (3) ◽  
pp. 597-609
Author(s):  
Y. ITO ◽  
N. TASHIRO
Keyword(s):  
Electrical Stimulation ◽  
Membrane Potential ◽  
Longitudinal Muscle ◽  
Spike Generation ◽  
Somatic Muscle ◽  
Membrane Potential Change ◽  
Maximum Slope ◽  
Phasic Contraction ◽  
Sustained Contraction ◽  
Electrical Activities

1. The mechanical and electrical activities of the longitudinal somatic muscle of the nereid Tylorrynchus heterochaetus were studied by intra- and extracellular stimulating methods. 2. The contraction elicited by electrical stimulation under isometric conditions consisted of two components, i.e. early phasic contraction and sustained contraction. The sustained contraction lasted more than 1 min after the cessation of the tetanic stimulation. 3. The membrane potential was 62.8 mV, and spontaneous discharges with overshoot (mean 18 mV) were recorded. A similar amplitude of the spike could be recorded by the intra-cellular polarizing method. 4. The maximum slope of the membrane potential change against a tenfold change in [K]o was 39 mV in the presence of Na+ and 48 mV in the absence of Na+. 5. The membrane was hyperpolarized by reduction of [Na]o but not by reduction of [Cl]o. 6. Tetrodotoxin (10-5 g/ml) blocked neither spontaneous spike generation nor spikes evoked by electrical stimulation. 7. The spike amplitude (overshoot) was proportionally increased with increased [Ca]o in the absence of Na+. The electrical threshold and the membrane potential remained the same in the ranges of 2 and 200 mM [Ca]o in the absence of Na+. 8. Sr2+ and Ba2+ could produce spike generation in the absence of Na+ and Ca2+. Prolongation of the spike (plateau) was observed when 20 mM Ba2+ was added to the solution containing no Na2+ and Ca2+. 9. The electrical and mechanical properties of the muscle were discussed in comparison with those observed of the longitudinal muscle of the earthworm.

Rate dependence and supernormality in excitability of guinea pig papillary muscle

1990 ◽  
Vol 259 (2) ◽  
pp. H290-H299 ◽  
Author(s):  
J. M. Davidenko ◽  
R. J. Levi ◽  
G. Maid ◽  
M. V. Elizari ◽  
M. B. Rosenbaum
Keyword(s):  
Guinea Pig ◽  
Action Potential ◽  
Conduction Block ◽  
Membrane Resistance ◽  
Stimulus Onset ◽  
Membrane Properties ◽  
Cardiac Tissues ◽  
Rate Dependent ◽  
Intracellular Stimulation ◽  
Premature Beats

It is well known that in most cardiac tissues an increase in rate results in a decrease of excitability and, eventually, conduction block. We used microelectrode techniques to evaluate the rate and time dependence of excitation latency in 27 isolated guinea pig papillary muscles (GPPM). Latency was measured as the interval between the stimulus onset and action potential upstroke. When the intensity of current was just suprathreshold, prolongation of the basic cycle length (BCL) from 300 to 1,000 ms produced an increase in latency or failure of excitation. Such behavior was observed with extracellular as well as intracellular stimulation. Rate-dependent changes in latency were maximal during the first 10-20 s following the rate change and reached a steady state in approximately 200 s. Application of premature beats revealed the presence of a "supernormal phase" in which latency abbreviated. Strength-interval and strength-duration curves demonstrated that changes in excitability accurately paralleled those observed in latency. Hence, supernormal excitability at the end of the phase 3 repolarization was consistently observed in all ventricular muscle experiments. Deceleration-induced decrease of excitability was attended by hyperpolarization, increase of action potential upstroke velocity (Vmax) and action potential amplitude, and decrease in membrane resistance. Our data suggest that paradoxical rate-related changes of excitability in GPPM are the result of changes in the passive membrane properties. Under conditions of depressed conductivity, this particular behavior may account for the occurrence of bradycardia-dependent block.

A Study of the Nitrogen-Containing Heterocycles on Copolyimide Properties for Proton Exchange Membranes

2013 ◽  
Vol 401-403 ◽  
pp. 563-566 ◽  
Author(s):  
Yu Han Li ◽  
Wei Jian Wang ◽  
Yu Fei Chen ◽  
Lei Wang
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Proton Conductivity ◽  
Water Uptake ◽  
Main Chain ◽  
Proton Exchange Membranes ◽  
Proton Exchange ◽  
Membrane Properties ◽  
Dimensional Changes ◽  
Sulfonated Polyimide

Containing pyrimidine and pyridine monomers were incorporated respectively into the main chain of a sulfonated polyimide in order to investigate the effect of nitrogen-containing heterocycles on membrane properties such as water uptake and proton conductivity. With increasing content of the nitrogen-containing heterocycles, water uptake of membranes and dimensional changes remarkable decrease. The copolymer showed higher thermal stability (desulfonation temperature up to 330 °C) and reasonable good mechanical properties. These membranes also showed higher proton conductivity, which was comparable or even higher than Nafion 117.

scholarly journals Membrane properties and spike generation in rat visual cortical cells during reversible cooling

2000 ◽  
Vol 522 (1) ◽  
pp. 59-76 ◽  
Author(s):  
Maxim Volgushev ◽  
Trichur R. Vidyasagar ◽  
Marina Chistiakova ◽  
Tagrid Yousef ◽  
Ulf T. Eysel
Keyword(s):  
Membrane Properties ◽  
Spike Generation ◽  
Cortical Cells ◽  
Visual Cortical

scholarly journals Diffuse approximation for identification of the mechanical properties of microcapsules

2020 ◽  
pp. 108128652097760
Author(s):  
Carlos Quesada ◽  
Claire Dupont ◽  
Pierre Villon ◽  
Anne-Virginie Salsac
Keyword(s):  
Mechanical Properties ◽  
Active Material ◽  
Liquid Core ◽  
Constitutive Law ◽  
Data Driven ◽  
Membrane Properties ◽  
Mechanical Resistance ◽  
Data Set ◽  
Diffuse Approximation ◽  
Capsule Size

A novel data-driven real-time procedure based on diffuse approximation is proposed to characterize the mechanical behavior of liquid-core microcapsules from their deformed shape and identify the mechanical properties of the submicron-thick membrane that protects the inner core through inverse analysis. The method first involves experimentally acquiring the deformed shape that a given microcapsule takes at steady state when it flows through a microfluidic microchannel of comparable cross-sectional size. From the mid-plane capsule profile, we deduce two characteristic geometric quantities that uniquely characterize the shape taken by the microcapsule under external hydrodynamic stresses. To identify the values of the unknown rigidity of the membrane and of the size of the capsule, we compare the geometric quantities with the values predicted numerically using a fluid-structure-interaction model by solving the three-dimensional capsule-flow interactions. The complete numerical data set is obtained off-line by systematically varying the governing parameters of the problem, i.e. the capsule-to-tube confinement ratio, and the capillary number, which is the ratio of the viscous to elastic forces. We show that diffuse approximation efficiently estimates the unknown mechanical resistance of the capsule membrane. We validate the data-driven procedure by applying it to the geometric and mechanical characterization of ovalbumin microcapsules (diameter of the order of a few tens of microns). As soon as the capsule is sufficiently deformed to exhibit a parachute shape at the rear, the capsule size and surface shear modulus are determined with an accuracy of 0.2% and 2.7%, respectively, as compared with 2–3% and 25% without it, in the best cases (Hu et al. Characterizing the membrane properties of capsules flowing in a square-section microfluidic channel: Effects of the membrane constitutive law. Phys Rev E 2013; 87(6): 063008). Diffuse approximation thus allows the capsule size and membrane elastic resistance to be provided quasi-instantly with very high precision. This opens interesting perspectives for industrial applications that require tight control of the capsule mechanical properties in order to secure their behavior when they transport active material.

Electrical and Mechanical Properties of the Red and White Muscles in the Silver Carp

1972 ◽  
Vol 57 (2) ◽  
pp. 551-567
Author(s):  
T. YAMAMOTO
Keyword(s):  
Mechanical Properties ◽  
White Muscle ◽  
Silver Carp ◽  
Membrane Resistance ◽  
Resting Potential ◽  
Resting Membrane Potential ◽  
Mechanical Responses ◽  
Red Muscle ◽  
Red And White Muscles ◽  
Specific Membrane

1. Electrical and mechanical properties of the red muscle (M. levator pinnae pectoralis) and white muscle (M. levator pinnae lateralis abdominis) in the silver carp (Carassius auratus Linné) were investigated by using caffeine and thymol. 2. A complete tetanus could be produced in the red muscle. But in the white muscle no tetanus was produced and there was a gradual decrease in tension during continuous stimulation, even at a frequency of 1 c/s or less. 3. Caffeine (0.5-1 mM) and thymol (0.25-0.5 mM) potentiated the twitch tension in both muscles without an increase in the resting tension; they produced a contracture in both muscles when the concentration was increased further. 4. The falling phase of the active state of contraction was nearly the same in both muscles and was prolonged by caffeine (0.5 mmM) and by thymol (0.25 mM). 5. The resting membrane potential of the red muscle was scarcely affected by caffeine (0.5-5 mM), whereas in the white muscles a depolarization of 10 mV was observed with caffeine of more than 2 mM. The resting potential of both muscles was little changed by o.25 mm thymol. However, at a concentration of more than 0.5mM thymol depolarized the membrane in both muscles to the same extent. 6. In caffeine (2-3 mM) solution the mean specific membrane resistance was reduced from 8.8 kΩ cm2 to 6.0 kΩ cm2 in the red muscle, and from 5.0 kΩ cm2 to 2.7 kΩ cm2 in the white muscle. In thymol (0.5-1 mM) solution it was reduced from 11.2 kΩcm2 to 6.5 kΩ cm2 in the red muscle, and from 5.4kΩ cm2 to 3.1 kΩ) cm2 in the white muscle. The specific membrane capacitance, calculated from the time constant and the membrane resistance, remained more or less the same in both muscles after a treatment with these agents. 7. Electrical properties of the muscles and the effects of caffeine and thymol on mechanical responses suggest that there are no fundamental differences between red and white muscles except for the excitation-contraction coupling. A lack of summation of twitch, a successive decline of twitch, and inability to produce potassium contracture in the white muscle may be due to the fact that the Ca-releasing mechanism is easily inactivated by depolarization of the membrane.

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