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.

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.

Electrotonic current spread in colonic smooth muscle

1988 ◽  
Vol 254 (5) ◽  
pp. G702-G710 ◽  
Author(s):  
J. D. Huizinga ◽  
E. Chow
Keyword(s):  
Membrane Potential ◽  
Slow Wave ◽  
Longitudinal Muscle ◽  
Circular Muscle ◽  
Muscle Cells ◽  
Human Colon ◽  
Membrane Properties ◽  
Electrotonic Coupling ◽  
Current Spread ◽  
Space Constant

Current-induced changes in the membrane potential (electrotonic potentials) were measured intracellularly. The electrotonic potentials were seen to decay exponentially over many cells, suggesting electrotonic current spread. The characteristics of the electrotonic current spread were used to determine passive membrane properties of both circular and longitudinal muscle cells of human and dog colon. Electrotonic current spread was first determined along the long axes of the cells. The space constant of the circular muscle of human colon was 2.14 mm and that of the longitudinal muscle was 1.63 mm. The space constants for the dog colon were similar. The value for the time constant of dog colon circular muscle was 160 ms, whereas much higher time constants, averaging between 500 and 800 ms, were recorded from dog longitudinal muscle and both human colon muscle layers. These data suggest good electrotonic coupling in all tissues studied, along the long axes of the cells. They further suggest a relatively high membrane resistance and junctional resistance in the longitudinal muscle. Electrotonic coupling along the short axes of circular muscle cells, along the long axis of the colon, was studied in the dog. The space constant was 0.43 mm, suggesting a relatively high resistance to current flow along the short axes of the cells. In addition, along the short axes of the cells from the submucosa to the myenteric plexus side (i.e., in radial direction) a gradient was observed in resting membrane potential, slow-wave amplitude, and rate of rise of the slow-wave upstroke.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Effects of ouabain on background and voltage-dependent currents in canine colonic myocytes

1990 ◽  
Vol 259 (3) ◽  
pp. C402-C408 ◽  
Author(s):  
E. P. Burke ◽  
K. M. Sanders
Keyword(s):  
Membrane Potential ◽  
Potential Gradient ◽  
Circular Muscle ◽  
Input Resistance ◽  
Pump Current ◽  
Muscle Layer ◽  
Membrane Properties ◽  
Resting Potential ◽  
Voltage Dependent ◽  
In Cells

Previous studies have suggested that the membrane potential gradient across the circular muscle layer of the canine proximal colon is due to a gradient in the contribution of the Na(+)-K(+)-ATPase. Cells at the submucosal border generate approximately 35 mV of pump potential, whereas at the myenteric border the pump contributes very little to resting potential. Results from experiments in intact muscles in which the pump is blocked are somewhat difficult to interpret because of possible effects of pump inhibitors on membrane conductances. Therefore, we studied isolated colonic myocytes to test the effects of ouabain on passive membrane properties and voltage-dependent currents. Ouabain (10(-5) M) depolarized cells and decreased input resistance from 0.487 +/- 0.060 to 0.292 +/- 0.040 G omega. The decrease in resistance was attributed to an increase in K+ conductance. Studies were also performed to measure the ouabain-dependent current. At 37 degrees C, in cells dialyzed with 19 mM intracellular Na+ concentration [( Na+]i), ouabain caused an inward current averaging 71.06 +/- 7.49 pA, which was attributed to blockade of pump current. At 24 degrees C or in cells dialyzed with low [Na+]i (11 mM), ouabain caused little change in holding current. With the input resistance of colonic cells, pump current appears capable of generating at least 35 mV. Thus an electrogenic Na+ pump could contribute significantly to membrane potential.

Memoirs: Peristalsis in the Malpighian Tubules of Diptera, Preliminary Account: with a note on the Elimination of Calcium Carbonate from the Malpighian Tubules of Drosophila Funebris

1925 ◽  
Vol s2-69 (275) ◽  
pp. 385-398
Author(s):  
L. EASTHAM
Keyword(s):  
Calcium Carbonate ◽  
Basement Membrane ◽  
Longitudinal Muscle ◽  
The Body ◽  
Malpighian Tubules ◽  
Preliminary Account ◽  
Longitudinal Muscles ◽  
Adult Drosophila

1. The proximal regions of the Malpighian tubules of Drosopbila funebris and Calliphora erythro cephala are supplied with systems of circular and longitudinal muscles external to the basement membrane. 2. These muscles are continuous with those of the mid-gut. 3. There is a terminal muscle to each anterior tubule in Drosophila funebris connected to the alar muscles of the pericardial septum. 4. Peristalsis has been observed in the proximal regions of the tubules, caused by the circular muscles. 5. The tubules exhibit a waving movement, probably due to the longitudinal muscle-bands of the lower or proximal ends of the tubules. 6. Calcium carbonate is stored in the terminal portions of the anterior tubules of Drosophila funebris. 7. This calcium carbonate is not eliminated at the beginning of metamorphosis, but is passed to the gut about the sixth day of pupal life, and is only expelled from the body on the emergence of the adult. 8. Calcium carbonate is found in the Malpighian tubules of the adult Drosophila funebris.

scholarly journals The Ionic Basis of the Resting Potential in a Cross-Striated Muscle of the Aquatic Snail Lymnaea Stagnalis

1984 ◽  
Vol 108 (1) ◽  
pp. 305-314
Author(s):  
B. L. BREZDEN ◽  
D. R. GARDNER
Keyword(s):  
Membrane Potential ◽  
Lymnaea Stagnalis ◽  
Striated Muscle ◽  
Potassium Concentration ◽  
Muscle Cells ◽  
Resting Potential ◽  
Extracellular Potassium ◽  
Heart Ventricle ◽  
Sodium Permeability ◽  
Ionic Basis

The mean resting potential in the heart ventricle muscle cells of the freshwater snail Lymnaea stagnalis was found to be −61.2±3.5 (˙˙) mV (ranging from −56mV to −68mV). The average intracellular potassium concentration was estimated to be 51.5±14.6(˙˙) m (ranging from 27.8 m to 77.3 m). The membrane of the heart ventricle muscle cells appears to be permeable to both potassium and chloride, as changes in the extracellular concentration of either of these ions resulted in a change in the membrane potential. A ten-fold change in the extracellular potassium concentration was associated with a 50.4±3.8(˙˙) mV slope when the potassium concentration was above about 6 m. Deviations from the straight-line relation predicted for a potassium electrode could be accounted for by introducing a term for sodium permeability. The ionic basis of the membrane potential in these cells can be described by a modified form of the Goldman-Hodgkin- Katz equation.

Thermal acclimation in a crustacean neuromuscular system

1982 ◽  
Vol 98 (1) ◽  
pp. 39-47
Author(s):  
P. J. Stephens ◽  
H. L. Atwood
Keyword(s):  
Membrane Potential ◽  
Muscle Fibre ◽  
Time Constant ◽  
Potential Temperature ◽  
Shore Crab ◽  
Acclimation Temperature ◽  
Muscle Fibres ◽  
Fibre Membrane ◽  
The Pacific ◽  
Different Temperatures

1. Effects of temperature on the muscle fibre membrane and synapses of stretcher muscle preparations made from autotomized limbs of the Pacific shore crab (Pachygrapsus crassipes) were investigated. 2. Acclimation of the crabs to different temperatures modified properties of both muscle fibre membrane and synapses. 3. Increased temperature produced an increase in membrane potential of the muscle fibres. A semi-log plot of these data revealed two linear phases of the membrane potential-temperature relationship, with a change in slope near the acclimation temperature. 4. Maximum values for excitatory junction potential (EJP) amplitude and time constant of EJP decay, and minimum values for facilitation were obtained at temperatures close to the acclimation temperature. It is suggested that the decline in EJP amplitude and time constant of decay produced by deviations in temperature from the acclimation temperature is compensated for by an increase in the amount of facilitation. In this way, maximum tension can be produced by the stretcher muscle in a range of at least 8 degrees C around the acclimation temperature.

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