Related Experiment Video
Updated: Jun 17, 2026
11:12
Sequential Photo-bleaching to Delineate Single Schwann Cells at the Neuromuscular Junction
Published on: January 11, 2013
Non-quantal acetylcholine release at the neuromuscular junction
F Vyskocil1, A I Malomouzh, E E Nikolsky
1Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic. vyskocil@biomed.cas.cz
Physiological Research
|January 12, 2010
Summary
Non-quantal acetylcholine release (NQR) is a crucial trophic factor for neuromuscular junctions. NQR supports muscle development, enhances adult synapse function, and influences skeletal muscle contractility.
Area of Science:
- Neuroscience
- Cell Biology
- Muscle Physiology
Background:
- Two primary mechanisms of acetylcholine (ACh) release exist at resting motor nerve terminals: quantal and non-quantal (NQR).
- Non-quantal release constitutes a significant portion of total ACh release, particularly at rest.
- NQR plays a vital role as a trophic factor in both developing and adult neuromuscular contacts.
Purpose of the Study:
- To summarize basic research on the role of non-quantal acetylcholine release (NQR).
- To highlight NQR's importance as a trophic factor in neuromuscular junction development and maintenance.
- To elucidate NQR's diverse functions in adult neuromuscular synapses.
Main Methods:
- Review of existing basic research on non-quantal acetylcholine release.
- Analysis of NQR's impact on endplate development and adult neuromuscular contacts.
- Examination of NQR's influence on subsynaptic membrane excitability, resting potential, and receptor desensitization.
Main Results:
- NQR aids in eliminating polyneural innervation during muscle fiber development.
- NQR enhances adult subsynaptic membrane excitability and protects resting membrane potential.
- NQR modulates endplate potentials, regulates the NO cascade and chloride transport, activates the Na+/K+-pump, influences quantal release synchronization, and affects skeletal muscle contractility.
Conclusions:
- Non-quantal acetylcholine release is an essential trophic factor with multifaceted roles.
- NQR is critical for proper neuromuscular junction development and function throughout life.
- Understanding NQR mechanisms provides insights into neuromuscular disorders and potential therapeutic targets.
More Related Videos
10:45Levator Auris Longus Preparation for Examination of Mammalian Neuromuscular Transmission Under Voltage Clamp Conditions
Published on: May 5, 2018
12:18The Neuromuscular Junction: Measuring Synapse Size, Fragmentation and Changes in Synaptic Protein Density Using Confocal Fluorescence Microscopy
Published on: December 26, 2014
Related Concept Videos
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...
01:29Relaxation 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.
01:19The 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...
01:23Cholinergic Neurons: Neurotransmission
Cholinergic neurotransmission involves the synthesis and the release of acetylcholine (ACh) in order to transmit nerve impulses across the synapse. The process begins with the synthesis of acetyl CoA, a precursor for ACh, from ATP, acetate, and coenzyme A in the mitochondria. Choline, another vital precursor, is transported inside the neuron through choline transporters, including high-affinity choline transporter CHT1, low-affinity choline transporter CTL1, and lower-affinity choline...
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...
01:26Chemical 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...