Excitation Secretion Coupling
Excitation Secretion Coupling - Related Videos
01:20
Excitation-Contraction Coupling in Skeletal Muscles
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2025
Excitation-contraction coupling is a series of events that occur between generating an action potential and initiating a muscle contraction. It occurs at the triad, a structure found in skeletal muscle fibers that comprise a T-tubule and terminal cisternae of the sarcoplasmic reticulum on each side. These triads are visible in longitudinally sectioned muscle fibers. They are typically located at the A-I junction — the junction between the A and I bands of the sarcomere. When an action potential...
08:29
Assessment of Myofilament Ca2+ Sensitivity Underlying Cardiac Excitation-contraction Coupling
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Cited by 9 •
2016
This paper describes a protocol that assesses the changes of myofilament Ca2+ sensitivity during contraction in isolated cardiac myocytes from rat heart. Together with cardiac electrophysiology, systolic/diastolic cytosol Ca2+ levels and contraction/relaxation, this measurement is imperative in underpinning the mechanisms mediating cardiac excitation-contraction coupling in healthy and diseased hearts.
07:39
Determination of the Excitation and Coupling Rates Between Light Emitters and Surface Plasmon Polaritons
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2018
This protocol describes the instrumentation for determining the excitation and coupling rates between light emitters and Bloch-like surface plasmon polaritons arising from periodic arrays.
12:33
Corticospinal Excitability Modulation During Action Observation
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Cited by 22 •
2013
Single-pulse transcranial magnetic stimulation over the primary motor cortex, neuronavigation, and registration of electromyographic activity of hand muscles were used in this study to explore corticospinal excitability while participants were observing action sequences.
12:13
Assessing Primary Motor Cortex Excitability and Excitability Modulation by Pairing Transcranial Magnetic Stimulation with Electromyography
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2025
Here, we present a protocol outlining the methodology to assess primary motor cortex excitability and excitability modulation using transcranial magnetic stimulation (TMS) paired with electromyography (EMG).
FAQs
Their opening provides the critical link between membrane depolarization and vesicle activation. Once depolarization reaches the cell surface, these channels permit calcium ions to enter the cell, where calcium activates synaptic or secretory vesicles. The vesicles then fuse with the membrane and release their chemical contents through exocytosis, converting an electrical signal into secretion.
Calcium entry gives the electrical signal a direct molecular trigger for membrane fusion. Depolarization alone does not complete secretion; opening of voltage-gated calcium channels allows calcium ions to activate the vesicles responsible for release. This coupling explains how changes in membrane activity can regulate neurotransmitter or hormone output in excitable and secretory cells.
The same overall signaling relationship applies across these cell types, but the released chemical messenger differs by biological context. In neurons, the process supports synaptic transmission; in neuroendocrine cells and endocrine tissues, it supports hormone release. Comparing these systems helps biology connect a shared calcium-dependent secretory mechanism with distinct forms of cellular communication.
Disruption at either stage can interfere with regulated secretion. If calcium signaling is changed, electrical activity may no longer activate vesicles appropriately. If vesicle trafficking is disturbed, activated vesicles may not reach or fuse with the membrane effectively. Such changes are relevant to disorders associated with abnormal secretion and help identify where cellular communication has failed.
A useful analysis follows the pathway from membrane depolarization to calcium-channel opening, calcium entry, vesicle activation, membrane fusion, and chemical release. Examining this sequence shows where electrical signaling becomes secretion and distinguishes calcium-related effects from problems in vesicle trafficking. The framework applies to studies of neurotransmitter release, hormone regulation, and secretory dysfunction.
The process provides a framework for understanding how cells regulate neurotransmitter and hormone release, while also identifying mechanisms that may be altered in disease. Research can therefore focus on calcium signaling or vesicle trafficking as points of interest. Drugs designed to modify cellular secretion may use this knowledge to influence communication in neurons or endocrine systems.