Video Experimental Relacionado
Updated: Sep 9, 2026
17:05
Loading a Calcium Dye into Frog Nerve Endings Through the Nerve Stump: Calcium Transient Registration in the Frog Neuromuscular Junction
Published on: July 8, 2017
¿Está el amortiguamiento extracelular del calcio involucrado en la regulación de la liberación del transmisor en la
Nature
|November 3, 1983
Resumen
El amortiguamiento del calcio inesperadamente disminuyó la liberación del transmisor en la unión neuromuscular. Esto sugiere que los niveles de calcio en la hendidura sináptica son más altos que el fluido extracelular a granel, lo que afecta la eficiencia sináptica.
Área de la Ciencia:
- La neurociencia es la neurociencia.
- Biología celular Biología celular.
- La biofísica es la biofísica.
Sus antecedentes:
- La actividad sináptica implica flujos iónicos a través de las membranas.
- Los flujos iónicos alteran las concentraciones de iones extracelulares en las brechas sinápticas.
- El influjo de calcio es crítico para la liberación de neurotransmisores.
Objetivo del estudio:
- Para investigar el papel del agotamiento extracelular del calcio en la liberación del transmisor.
- Para determinar si el mantenimiento constante del calcio extracelular afecta la liberación cuantitativa.
Principales métodos:
- Se utilizan amortiguadores de calcio para estabilizar las concentraciones de calcio extracelular.
- Comparación de la liberación del transmisor en soluciones tamponadas frente a soluciones no tamponadas.
- Estudió la preparación neuromuscular de las ranas.
Principales resultados:
- Las soluciones tamponadas con calcio disminuyeron la liberación del transmisor.
- Este efecto se observó incluso cuando las concentraciones de calcio a granel eran idénticas.
- Indica una mayor concentración de calcio dentro de la hendidura sináptica que en el medio a granel.
Conclusiones:
- La concentración de calcio extracelular en la hendidura sináptica es probablemente más alta que en el medio extracelular a granel.
- Este alto calcio localizado puede regular la liberación del transmisor evocado.
- Sugiere un mecanismo fisiológico para controlar la eficiencia sináptica.
Más Videos Relacionados
10:45Levator Auris Longus Preparation for Examination of Mammalian Neuromuscular Transmission Under Voltage Clamp Conditions
Published on: May 5, 2018
11:12Registration of Calcium Transients in Mouse Neuromuscular Junction with High Temporal Resolution using Confocal Microscopy
Published on: December 1, 2021
Videos de Conceptos Relacionados
01:26Chemical Synapses
Chemical synapses are specialized sites between two neurons or between a neuron and a non-neuronal cell like a muscle, glandular or sensory cell.
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
01:27Feedback Regulation of Calcium Concentration
Calcium is an essential signaling molecule required for various cellular functions. Calcium pumps and ion channels on cell and organellar membranes, such as those on the endoplasmic reticulum (ER), regulate calcium concentrations inside the cell. They remain closed, keeping the cytosolic calcium levels low at a resting state.
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
01:29Neuromuscular Junction And Blockade
The site of chemical communication between a motor neuron and a muscle fiber is called the neuromuscular junction (NMJ). The end of the motor neuron at the NMJ divides into a cluster of synaptic end bulbs. The cytoplasm of these bulbs consists of synaptic vesicles enclosing acetylcholine molecules, the principal neurotransmitter released at the NMJ. The region opposite the synaptic bulb that ends in the muscle fiber is called the motor end plate, which has acetylcholine receptors. Within the...
01:19The Neuromuscular Junction
The nervous system consists of complex motor neuron circuits, including upper motor neurons originating from the cerebral cortex and lower motor neurons starting in the spinal cord, coordinating both voluntary and involuntary movements. Among these, somatic motor neurons activate skeletal muscles and are classified into alpha, beta, and gamma types. Alpha neurons are vital for voluntary movement coordination, while gamma neurons adjust muscle spindle sensitivity, and the function of beta...
01:29Relaxation of Skeletal Muscles
The period of muscle contraction primarily influences the duration of stimulation at the neuromuscular junction (NMJ), the presence of free calcium ions in the sarcoplasm, and the availability of energy or ATP to support contractions.
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open.
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open.
01:26Chemical Synapses
Chemical synapses are specialized sites between two neurons or between a neuron and a non-neuronal cell like a muscle, glandular or sensory cell.
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...