Role of Sodium Ions in the Response of the Frequency of Miniature End-plate Potentials to Osmotic Changes in the Neuromuscular Junction

Nature ◽  
1969 ◽  
Vol 222 (5189) ◽  
pp. 169-171 ◽  
Author(s):  
S. MUCHNIK ◽  
R. A. VENOSA
Keyword(s):  
Neuromuscular Junction ◽  
Sodium Ions ◽  
End Plate

Pharmacological elevation of cyclic AMP and transmitter release at the mouse neuromuscular junction

1988 ◽  
Vol 66 (2) ◽  
pp. 207-212 ◽  
Author(s):  
W. F. Dryden ◽  
Y. N. Singh ◽  
T. Gordon ◽  
G. Lazarenko
Keyword(s):  
Cyclic Amp ◽  
Neuromuscular Junction ◽  
Cholera Toxin ◽  
Time Course ◽  
Second Messengers ◽  
Phosphodiesterase Inhibitors ◽  
Spontaneous Release ◽  
End Plate ◽  
Release Of Acetylcholine

Intracellular recordings of spontaneous and evoked end-plate potentials have been made at the neuromuscular junction of mouse hemidiaphragms to determine a possible role of cyclic AMP (cAMP) in the release of acetylcholine from presynaptic terminals. Spontaneous release, as determined from the frequency of miniature end-plate potentials, was increased by drugs that inhibit phosphodiesterase: isobutylmethylxanthine (IBMX), SQ 20,009, theophylline, and caffeine; drugs that stimulate adenylate cyclase: forskolin, fluoride, and cholera toxin, and the stable analogue of cAMP: 8-bromo-cAMP but not dibutyryl cAMP. Release increased with time during maintained exposure to the drugs and generally followed a simple exponential time course with time constants ranging from 8 to 17 min at 20 °C, except for SQ 20,009 and cholera toxin which required longer exposure times for effect. The order of potency of the phosphodiesterase inhibitors was IBMX = SQ 20,009 > theophylline = caffeine. This is consistent with an effect mediated by an increase in cAMP concentrations within the nerve terminal. Evoked release, determined from the quantal content of the end-plate potential, was increased to a lesser extent than spontaneous release. The results are discussed with reference to the possible involvement of second messengers in the release of vesicles from nerve terminals in vertebrate synapses.

The role of sodium ions in the thermoluminescence peaks of laboratory-irradiated natural quartz

2021 ◽  
Vol 141 ◽  
pp. 106539
Author(s):  
Tran Ngoc ◽  
Ho Van Tuyen ◽  
Le Anh Thi ◽  
Le Xuan Hung ◽  
Nguyen Xuan Ca ◽  
...  
Keyword(s):  
Sodium Ions ◽  
Natural Quartz

scholarly journals What Density of Magnetosheath Sodium Ions Can Provide the Observed Decrease in the Magnetic Field of the “Double Magnetopause” during the First MESSENGER Flyby?

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1168
Author(s):  
Elena Belenkaya ◽  
Ivan Pensionerov
Keyword(s):  
Magnetic Field ◽  
Analytical Approach ◽  
Field Structure ◽  
Sodium Ions ◽  
Plasma Parameters ◽  
Calculation Results ◽  
Magnetizing Current ◽  
The Magnetic Field ◽  
Density Excess

On 14 January 2008, the MESSENGER spacecraft, during its first flyby around Mercury, recorded the magnetic field structure, which was later called the “double magnetopause”. The role of sodium ions penetrating into the Hermean magnetosphere from the magnetosheath in generation of this structure has been discussed since then. The violation of the symmetry of the plasma parameters at the magnetopause is the cause of the magnetizing current generation. Here, we consider whether the change in the density of sodium ions on both sides of the Hermean magnetopause could be the cause of a wide diamagnetic current in the magnetosphere at its dawn-side boundary observed during the first MESSENGER flyby. In the present paper, we propose an analytical approach that made it possible to determine the magnetosheath Na+ density excess providing the best agreement between the calculation results and the observed magnetic field in the double magnetopause.

scholarly journals ROLE of exercise in maintaining the integrity of the neuromuscular junction

2013 ◽  
Vol 49 (3) ◽  
pp. 315-324 ◽  
Author(s):  
Hiroshi Nishimune ◽  
John A. Stanford ◽  
Yasuo Mori
Keyword(s):  
Neuromuscular Junction

Influence of presynaptic receptors on neuromuscular transmission in rat

1982 ◽  
Vol 242 (5) ◽  
pp. C366-C372 ◽  
Author(s):  
D. F. Wilson
Keyword(s):  
Transmitter Release ◽  
Action Potentials ◽  
Physiological Function ◽  
Motor Nerve ◽  
Presynaptic Receptors ◽  
End Plate ◽  
Feedback Pathway ◽  
Partial Blockade ◽  
Ach Receptors

The presence and physiological significance of acetylcholine (ACh) receptors on motor nerve terminals was examined at the rat diaphragm neuromuscular junction. Intracellular recording techniques were used to monitor end-plate potentials (EPP), miniature end-plate potentials (MEPP), and resting potentials of the muscle fibers. Muscle action potentials were blocked by the cut-muscle technique. Quantal release was determined by the ratio EPP/MEPP, after correcting for nonlinear summation. Blockade of acetylcholinesterase with eserine and neostigmine was tested to determine the influence of residual ACh on transmitter release. Partial blockade of ACh receptors with curare was examined to further clarify the role of these presynaptic receptors. The experiments demonstrate that residual ACh inhibits transmitter release and that blockade of ACh receptors enhances transmitter release. It is concluded that presynaptic ACh receptors exist and that they serve an important physiological function. It is suggested that the presynaptic ACh receptors normally serve to limit transmitter release in a negative feedback pathway.

The Role of Additives in the Electroreduction of Sodium Ions in Chloroaluminate-Based Ionic Liquids

2005 ◽  
Vol 152 (1) ◽  
pp. E9 ◽  
Author(s):  
Ketack Kim ◽  
Christopher Lang ◽  
Paul A. Kohl
Keyword(s):  
Ionic Liquids ◽  
Sodium Ions

The role of sodium chloride in the process of induction by lithium chloride in cells of the Rana pipiens gastrula

Development ◽  
1968 ◽  
Vol 19 (3) ◽  
pp. 387-396
Author(s):  
Lester G. Barth ◽  
Lucena J. Barth
Keyword(s):  
Sodium Chloride ◽  
Culture Medium ◽  
Rana Pipiens ◽  
Divalent Cations ◽  
Pigment Cells ◽  
Distilled Water ◽  
Sodium Ions ◽  
Monovalent Cations ◽  
High Concentration

A study of the effects of a series of monovalent cations, Li+, Na+ and K+, and a series of divalent cations, Mn2+, Ca2+ and Mg2+, upon small aggregates of cells taken from the presumptive epidermis of Rana pipiens gastrulae revealed that these ions induce nerve and pigment cells (Barth, 1965). The effectiveness of both series of ions as inductors was similar to their effects on decreasing the electrophoretic mobility of DNA as determined by Ross & Scruggs (1964). When it was found that sucrose in glass-distilled water also would induce nerve and pigment cells the role of ions as inductors came under closer scrutiny. A study of the nature of the induction by sucrose revealed that a relatively high concentration of sodium ions was necessary in the culture medium used after sucrose treatment (Barth, 1966).

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