Influence of nitrate and other anions on fast and slow contractions of crab muscle

1968 ◽  
Vol 46 (1) ◽  
pp. 1-9 ◽  
Author(s):  
H. L. Atwood
Keyword(s):  
Membrane Potential ◽  
Muscle Fiber ◽  
Membrane Resistance ◽  
Single Muscle ◽  
Fiber Membrane ◽  
Tension Development ◽  
Muscle Fiber Membrane ◽  
Slow Contraction ◽  
Potential Threshold ◽  
Bathing Fluid

The effects of bromide, nitrate, iodide, and thiocyanate ions on the neurally evoked fast and slow contractions of a crab muscle were investigated. Both types of contraction were depressed in bromide and nitrate. In iodide and thiocyanate, the slow contraction was often depressed but the fast contraction was potentiated. The foreign anions increased muscle fiber membrane resistance and the amplitudes of both fast and slow postsynaptic potentials. Records of tension development in single muscle fibers showed that more stimulating current was required to produce a given tension in nitrate than in the standard bathing fluid; this change was related to hyperpolarization of the muscle fiber membrane in nitrate. Potassium contractures also were inhibited by nitrate, because of the less effective depolarization of the cell membrane by potassium ion in the presence of nitrate. No marked shift in the membrane potential threshold for contraction occurred after treatment with the foreign anions.

scholarly journals Permeability of Alkali Metal Cations in Lobster Muscle

1968 ◽  
Vol 51 (3) ◽  
pp. 399-425 ◽  
Author(s):  
Harold Gainer ◽  
Harry Grundfest
Keyword(s):  
Membrane Potential ◽  
Muscle Fiber ◽  
Single Muscle ◽  
Alkali Metal Cations ◽  
Fiber Membrane ◽  
Osmotic Permeability ◽  
Hyperosmotic Condition ◽  
Time Courses ◽  
Muscle Fiber Membrane ◽  
External K

Single muscle fibers from lobster walking legs are effectively impermeable to Na, but are permeable to K. They shrink in hyperosmotic NaCl; they swell in low NaCl media which are hyposmotic or which are made isosmotic with the addition of KCl. In conformity, the membrane potential is relatively insensitive to changes in external Na, while it responds according to the Nernst relation for changes in external K. When the medium is made isosmotic or hyperosmotic with RbCl the volume and membrane potential changes are of essentially the same magnitudes as those in media enriched with KCl. The time courses for attaining equilibrium are slower, indicating that Rb is less permeant than K. Substitution of CsCl for NaCl (isosmotic condition) produces no change in volume of the muscle fiber. Addition of CsCl (hyperosmotic condition) causes a shrinkage which attains a steady state, as is the case in hyperosmotic NaCl. Osmotically, therefore, Cs appears to be no more permeant than is Na. However, the membrane depolarizes slowly in Cs-enriched media and eventually comes to behave as an ideal Cs electrode. Thus, the electrode properties of the lobster muscle fiber membrane may not depend upon the diffusional relations of the membrane and ions, and the osmotic permeability of the membrane for a given cation may not correspond with the electrophysiologically deduced permeability. Comparative data on the effects of NH4 and Li are also included and indicate several other degrees of complexity in the cell membrane.

Stabilization and rectification of muscle fiber membrane by tetrodotoxin

1960 ◽  
Vol 198 (5) ◽  
pp. 934-938 ◽  
Author(s):  
Toshio Narahashi ◽  
Takehiko Deguchi ◽  
Norimoto Urakawa ◽  
Yoshio Ohkubo
Keyword(s):  
Muscle Fiber ◽  
Muscle Fibers ◽  
Membrane Resistance ◽  
Frog Muscle ◽  
Resting Potential ◽  
Fiber Membrane ◽  
Delayed Rectification ◽  
Intracellular Microelectrodes ◽  
Cathodal Current ◽  
Muscle Fiber Membrane

The mode of action of tetrodotoxin on the frog muscle fiber membrane has been analyzed with the aid of intracellular microelectrodes. Tetrodotoxin of 10–7 concentration made the applied cathodal current ineffective in producing action potential, whereas the resting potential and resting membrane resistance underwent little or no change. With 10–8 tetrodotoxin the muscle fibers responded with the small action potentials at high critical depolarizations. These results can be explained on the basis of the membrane being stabilized by inactivation of the sodium-carrying mechanism. Although delayed rectification was not observed in normal muscle fibers, it became apparent in the fibers rendered inexcitable by tetrodotoxin. This finding, together with other evidence in the existing literature, supports an applicability of the sodium theory to the frog muscle fibers.

Lobster muscle and synapse respond to cortisol, a vertebrate hormone

1983 ◽  
Vol 61 (8) ◽  
pp. 836-840 ◽  
Author(s):  
D. Dixon ◽  
H. L. Atwood
Keyword(s):  
Membrane Potential ◽  
Neuromuscular Transmission ◽  
Physiological Role ◽  
Homarus Americanus ◽  
Membrane Resistance ◽  
Rapid Onset ◽  
Excitatory Postsynaptic Potentials ◽  
Fiber Membrane ◽  
Postsynaptic Potentials ◽  
Muscle Fiber Membrane

Cortisol (0.28 μmol∙L−1) applied to lobster (Homarus americanus) neuromuscular preparations produces a hyper-polarization in muscle fibers and an increase in amplitude of excitatory postsynaptic potentials. The effect appears to be surface-mediated, because of its rapid onset (within seconds). It is also Na+–K+ ATPase dependent, because ouabain blocks the effects. The effects are relatively short-lasting, and gradually subside within 15 min. The increase in excitatory postsynaptic potentials is attributed in part to increased quantal output of transmitter, and not to changes in muscle fiber membrane resistance. The effects of cortisol on neuromuscular transmission and membrane potential indicate that cortisol may have a physiological role in crustaceans.

Capacity of Muscle Fiber Membrane

1957 ◽  
Vol 188 (3) ◽  
pp. 423-429 ◽  
Author(s):  
I. Tasaki ◽  
S. Hagiwara
Keyword(s):  
Action Potential ◽  
Muscle Fiber ◽  
Impedance Measurement ◽  
Single Muscle ◽  
Muscle Action ◽  
Electric Impedance ◽  
Fiber Membrane ◽  
Membrane Capacity ◽  
Muscle Action Potential ◽  
Muscle Fiber Membrane

Using two or three microelectrodes inserted into single muscle fibers of the toad sartorius, the electric impedance of the muscle fiber membrane was measured with a.c. between 25 and 1500 cps. It was found that the capacity of the muscle fiber membrane is practically independent of the frequency of the measuring a.c. The membrane capacity determined from the time constant of potential rise in the foot of a propagated muscle action potential agrees with the value determined by a.c. impedance measurement. It was emphasized that the a.c. method of determining the cable constants of the muscle fiber (based on eq. 1 under methods) is simple and gives satisfactory results.

Effects of ?-endorphin on the development of denervation changes in rat muscle fiber membrane

1988 ◽  
Vol 19 (6) ◽  
pp. 550-555 ◽  
Author(s):  
A. V. Chikin ◽  
A. Kh. Urazaev ◽  
E. M. Volkov ◽  
G. I. Poletaev ◽  
Kh. S. Khamitov
Keyword(s):  
Muscle Fiber ◽  
Fiber Membrane ◽  
Rat Muscle ◽  
Muscle Fiber Membrane

scholarly journals Electromyography and Applications Based on the Interpretation of the Electrical Activity Associated with the Depolarization-Repolarization Cycle of the Muscle Fiber Membrane

2020 ◽  
Vol 71 (9) ◽  
pp. 325-336
Author(s):  
Teodor Dan Vacarus ◽  
Cristina Popescu ◽  
Adrian Moise ◽  
Gabriela Bucur
Keyword(s):  
Electrical Activity ◽  
Muscle Fiber ◽  
Industrial Robots ◽  
Processing Unit ◽  
Fiber Membrane ◽  
Analog To Digital ◽  
Prosthetic Limbs ◽  
Analog To Digital Conversion ◽  
Series Of Experiments ◽  
Muscle Fiber Membrane

The aim of this paper is to present the implementation of a method for data acquisition, processing and interpretation of the electrical activity associated with the muscle fiber membrane, generated as a result of the ionic pumps� action. By using a biofeedback shield (EKG/EMG shield) for differential amplification and analog signal filtering, an Arduino development board for analog to digital conversion and an external processing unit, a series of experiments were carried out. These referred to medical diagnosis and research, human-machine interfaces (control of a robotic joint which could be used for prosthetic limbs or industrial robots, as well as control of the computer � for video games, virtual reality, interaction with other devices), and monitoring and increasing sports performance. Due to its noninvasive characteristics, this technique, known as surface electromyography, proves to play a significant role in areas such as medical research, rehabilitation, ergonomics, sports etc.

Hypokalemic periodic paralysis: In vitro investigation of muscle fiber membrane parameters

1984 ◽  
Vol 7 (2) ◽  
pp. 110-120 ◽  
Author(s):  
Reinhardt Rüdel ◽  
Frank Lehmann-Horn ◽  
Kenneth Ricker ◽  
Gerald Küther
Keyword(s):  
Muscle Fiber ◽  
Periodic Paralysis ◽  
Fiber Membrane ◽  
Hypokalemic Periodic Paralysis ◽  
In Vitro Investigation ◽  
Muscle Fiber Membrane
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