Potassium-induced Depolarization
Potassium-induced Depolarization - Related Videos
08:31
FM Dye Cycling at the Synapse: Comparing High Potassium Depolarization, Electrical and Channelrhodopsin Stimulation
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Cited by 7 •
2018
Synaptic vesicle (SV) cycling is the core mechanism of intercellular communication at neuronal synapses. FM dye uptake and release are the primary means of quantitatively assaying SV endo- and exocytosis. Here, we compare all the stimulation methods to drive FM1-43 cycling at the Drosophila neuromuscular junction (NMJ) model synapse.
10:45
Monitoring Cleaved Caspase-3 Activity and Apoptosis of Immortalized Oligodendroglial Cells using Live-cell Imaging and Cleaveable Fluorogenic-dye Substrates Following Potassium-induced Membrane Depolarization
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Cited by 16 •
2012
Live-cell imaging of caspase-3 mediated apoptosis in immortalized N19-oligodendrocyte cell cultures using the NucView 488 caspase-3 substrate. This technique is applicable for programmed cell death assays in real-time in a variety of cell types and tissues.
03:06
Investigating Prolonged Depolarizing Afterpotential (PDA) in Drosophila Photoreceptors
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2025
This video demonstrates an experimental protocol to investigate the prolonged depolarizing afterpotential (PDA) in white-eyed Drosophila. The fly's eye is exposed to intense blue light pulses to convert the photopigment rhodopsin to metarhodopsin, initiating a signaling cascade that opens positive ion channels and causes membrane depolarization. Because blue light prevents the reconversion of metarhodopsin to rhodopsin, the continuous influx of positive ions results in sustained depolarization,...
03:41
Measurement of Evoked Potassium Ion Concentration Dynamics in Coronal Hippocampal Slices
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2025
The video demonstrates evoked potassium ion concentration dynamics on electrical stimulation of mouse coronal hippocampal brain slices. A bipolar stimulating electrode is inserted into the stratum radiatum of the CA3 region in the hippocampus, and a potassium-ion selective electrode is placed in the CA1 stratum radiatum. The electrical stimulation causes an action potential, resulting in potassium ion release. Finally, the lack of evoked potassium ion response in the presence of an inhibitory...
01:26
Regulation of Sodium and Potassium
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2024
The regulation of sodium and potassium ion concentrations in the human body is a complex process governed primarily by hormones such as aldosterone, antidiuretic hormone (ADH), and atrial natriuretic peptide (ANP). Sodium Regulation Sodium ions make up approximately 90% of extracellular cations, with a normal blood plasma concentration of 136–148 mEq/L. A decrease in blood volume and pressure triggers the release of renin from granular cells in the juxtaglomerular complex (JGC), primarily in...
FAQs
Raising extracellular potassium reduces the electrochemical gradient that normally drives potassium movement across the membrane. This shifts the potassium equilibrium potential and makes the membrane voltage less negative. The resulting change provides a controlled way to alter neuronal excitability without requiring direct stimulation, allowing investigators to examine how membrane voltage influences downstream electrical and synaptic events.
When the membrane depolarization reaches threshold, voltage-gated sodium and calcium channels can open. Sodium channel activation promotes action potentials, whereas calcium channel opening increases calcium influx. These events connect the initial voltage change to calcium-dependent signaling and neurotransmitter release, making the response useful for linking membrane excitability with functional communication between neurons.
Prolonged potassium-induced depolarization can produce channel inactivation and impaired cellular function. Although an initial voltage change may activate sodium and calcium channels, sustained exposure can reduce normal channel availability and disrupt the cell’s response. This distinction helps researchers interpret whether an observed effect reflects acute excitation or the consequences of extended membrane stress.
Investigators increase the extracellular potassium concentration while studying cultured neurons, brain slices, or isolated tissues. They can then examine changes associated with neuronal excitability, synaptic transmission, calcium-dependent signaling, or neurotransmitter release. The preparation determines which cellular or tissue-level response is most accessible, while the controlled ionic change provides a common experimental stimulus.
The approach is useful for examining how electrical activity influences calcium entry and how calcium signals support neurotransmitter release. It can also reveal relationships between membrane excitability and synaptic transmission in different experimental preparations. These applications make the method relevant to studies of neuronal signaling in both isolated cells and organized nervous tissue.
An early response may indicate that depolarization reached threshold and activated voltage-gated sodium or calcium channels, leading to action potentials, calcium influx, or neurotransmitter release. A later decline or abnormal response may instead reflect channel inactivation and impaired cellular function. Interpreting exposure duration is therefore important when connecting measurements to neuronal mechanisms.