The role of current flow in the propagation of cardiac muscle action potentials

1964 ◽  
Vol 279 (2) ◽  
pp. 192-194 ◽  
Author(s):  
Lloyd Barr ◽  
Winfried Berger
Keyword(s):  
Cardiac Muscle ◽  
Action Potentials ◽  
Current Flow ◽  
Muscle Action

scholarly journals Contraction and Action Potentials of Frog Heart Muscles Soaked in Sucrose Solution

1962 ◽  
Vol 46 (1) ◽  
pp. 35-56 ◽  
Author(s):  
William G. Van der Kloot ◽  
Nira S. Rubin
Keyword(s):  
Action Potential ◽  
Cardiac Muscle ◽  
Extracellular Space ◽  
Action Potentials ◽  
Sucrose Solution ◽  
Extracellular Fluid ◽  
Frog Heart

Isolated auricles or ventricles from the frog continue to contract, either spontaneously or when stimulated, for from 2 to 4 hours after they are placed in isotonic sucrose solution. After the muscles stop contracting in sucrose solution, contractility is partially restored when the muscles are placed in chloride Ringer's. However, contractility is usually not restored if the muscles are placed in sulfate Ringer's. Ventricles soaked in sucrose solution at 4–7°C continue to contract for 12 to 24 hours and during the first few hours in sucrose solution the contractions often are enhanced. Several types of experiment indicate that the sucrose solution does replace the Ringer's in the extracellular space. Auricles and ventricles also continue to conduct action potentials, with an overshoot, for from 30 to 360 minutes after being placed in sucrose solution. Muscles soaked in sucrose until they are inexcitable rapidly recover in chloride Ringer's but often fail to recover in sulfate Ringer's. The results are discussed in relation to theories about the generation of the action potential in cardiac muscle, and the role of the extracellular fluid in contraction.

scholarly journals Tetrodotoxin: A New Strategy to Treat Visceral Pain?

Toxins ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 496
Author(s):  
Ana Campos-Ríos ◽  
Lola Rueda-Ruzafa ◽  
Salvador Herrera-Pérez ◽  
Paula Rivas-Ramírez ◽  
José Antonio Lamas
Keyword(s):  
Action Potentials ◽  
Channel Blocker ◽  
Visceral Pain ◽  
Visceral Hypersensitivity ◽  
Afferent Neurons ◽  
Sodium Channel Blocker ◽  
Voltage Gated Sodium Channels ◽  
New Strategy ◽  
Specific Receptors

Visceral pain is one of the most common symptoms associated with functional gastrointestinal (GI) disorders. Although the origin of these symptoms has not been clearly defined, the implication of both the central and peripheral nervous systems in visceral hypersensitivity is well established. The role of several pathways in visceral nociception has been explored, as well as the influence of specific receptors on afferent neurons, such as voltage-gated sodium channels (VGSCs). VGSCs initiate action potentials and dysfunction of these channels has recently been associated with painful GI conditions. Current treatments for visceral pain generally involve opioid based drugs, ≠≠which are associated with important side-effects and a loss of effectiveness or tolerance. Hence, efforts have been intensified to find new, more effective and longer-lasting therapies. The implication of VGSCs in visceral hypersensitivity has drawn attention to tetrodotoxin (TTX), a relatively selective sodium channel blocker, as a possible and promising molecule to treat visceral pain and related diseases. As such, here we will review the latest information regarding this toxin that is relevant to the treatment of visceral pain and the possible advantages that it may offer relative to other treatments, alone or in combination.

Tetrodotoxin-resistant release of ATP from superfused rabbit detrusor muscle during electrical field stimulation in the presence of luciferin–luciferase

1984 ◽  
Vol 62 (1) ◽  
pp. 153-156 ◽  
Author(s):  
Archana Chaudhry ◽  
John W. Downie ◽  
Thomas D. White
Keyword(s):  
Action Potentials ◽  
Electrical Field Stimulation ◽  
Detrusor Muscle ◽  
Electrical Field ◽  
Stimulation Parameters ◽  
Rabbit Bladder ◽  
Firefly Luciferin ◽  
Rabbit Urinary Bladder ◽  
Stimulation Of

The present study was carried out to assess the possible role of ATP in the noncholinergic, nonadrenergic transmission in the rabbit urinary bladder. When rabbit detrusor muscle strips were superfused with medium containing firefly luciferin–luciferase and stimulated transmurally at low stimulation parameters, tetrodotoxin-sensitive contractions were obtained but no release of ATP could be detected. However, at somewhat higher stimulation parameters, release of ATP was observed. This release of ATP was not diminished by tetrodotoxin indicating that ATP was not likely released as a result of propagated action potentials in nerves. Because contractions persisted in the presence of tetrodotoxin, it is possible that the ATP might have been released as a result of direct electrical stimulation of the muscle. These results do not support the idea that ATP is released as a neurotransmitter in the rabbit bladder.

Latency of compound muscle action potentials of the anal sphincter after magnetic sacral stimulation

2001 ◽  
Vol 24 (9) ◽  
pp. 1232-1235 ◽  
Author(s):  
G.L. Morren ◽  
S. Walter ◽  
H. Lindehammar ◽  
O. Hallböök ◽  
R. Sjödahl
Keyword(s):  
Anal Sphincter ◽  
Action Potentials ◽  
Muscle Action ◽  
Compound Muscle Action Potentials ◽  
Sacral Stimulation

scholarly journals Propagation of Action Potentials and the Structure of the Nexus in Cardiac Muscle

1965 ◽  
Vol 48 (5) ◽  
pp. 797-823 ◽  
Author(s):  
L. Barr ◽  
M. M. Dewey ◽  
W. Berger
Keyword(s):  
Guinea Pig ◽  
Cardiac Muscle ◽  
Action Potentials ◽  
Structural Changes ◽  
Sucrose Solution ◽  
Electrical Coupling ◽  
Intercalated Discs ◽  
Sucrose Gap ◽  
Specialized Structure ◽  
Frog Atrium

The hypothesis that the nexus is a specialized structure allowing current flow between cell interiors is corroborated by concomitant structural changes of the nexus and changes of electrical coupling between cells due to soaking in solutions of abnormal tonicity. Fusiform frog atrial fibers are interconnected by nexuses. The nexuses, desmosomes, and regions of myofibrillar attachment of this muscle are not associated in a manner similar to intercalated discs of guinea pig cardiac muscle. Indeed, nexuses occur wherever cell membranes are closely apposed. Action potentials of frog atrial bundles detected extracellularly across a sucrose gap change from monophasic to diphasic when the gap is shunted by a resistor. This indicates that action potentials are transmitted across the gap when sufficient excitatory current is allowed to flow across the gap. When the sucrose solution in the gap is made hypertonic, propagation past the gap is blocked and the resistance between the cells in the gap increases. Electron micrographs demonstrate that the nexuses of frog atrium and guinea pig ventricle are ruptured by hypertonic solutions.

Mapping the Compound Muscle Action Potentials of Cricothyroid Muscle Using Electromyography in Thyroid Operations

2009 ◽  
Vol 250 (2) ◽  
pp. 293-300 ◽  
Author(s):  
Ben Selvan ◽  
Srinivasa Babu ◽  
M J. Paul ◽  
Deepak Abraham ◽  
Prasanna Samuel ◽  
...  
Keyword(s):  
Action Potentials ◽  
Muscle Action ◽  
Cricothyroid Muscle ◽  
Compound Muscle Action Potentials
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