Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Muscle Contraction

Muscle Contraction

Neuromuscular Junction And Blockade

Neuromuscular 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...

Local Anesthetics: Differential Sensitivity of Nerve Fibers

Local Anesthetics: Differential Sensitivity of Nerve Fibers

Local anesthetics (LAs) block the sodium channels of nerve trunks, sensory nerve endings, and neuromuscular junctions. Although LAs can block all kinds of nerves, the sensitivity of nerve fibers differs according to nerve types and structures. LAs are known to block myelinated fibers faster than unmyelinated ones. Also, they block pain or sensory neurons at low concentrations without affecting the motor neurons involved in muscle contractions. This helps relieve labor pain without affecting the...

The Neuromuscular Junction

The 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...

Motor Unit Stimulation

Motor Unit Stimulation

When the neuron of a motor unit fires an action potential, it triggers a series of events, leading to a twitch contraction in the muscle fibers. The process of excitation-contraction coupling is crucial in relaying the action potential to the muscle fibers.
The latent period of contraction marks the onset of excitation-contraction coupling, when the action potential propagates across the sarcolemma, preparing the muscle fibers for contraction. As the fibers enter the contraction phase, the...

Muscle Stimulation Frequency

Muscle Stimulation Frequency

The contraction strength of muscles is regulated by motor neurons, which modulate the frequency of action potentials dispatched to the motor units based on the body's requirements. This process of varying the muscle stimulation frequency allows muscles to contract with a force that is precisely tailored to the needs of the moment, whether lifting a feather or a heavy box.
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Relative frequencies of muscle specific kinase antibody myasthenia in 46 centres worldwide.

Brain : a journal of neurology·2026

Same author

Immunotherapy responsive startle with antibodies to voltage gated potassium channels.

BMJ case reports·2025

Same author

Subtype-specific atypical B cell profiles in myasthenia gravis reveal distinct immunopathological pathways.

Frontiers in immunology·2025

Same author

Evolution and significance of neuronal surface autoantibodies after Japanese encephalitis.

Journal of neuroimmunology·2025

Same author

GAD antibodies in neurological disease: a critical evaluation of the utility and treatment implications of GAD antibodies in clinical practice.

Journal of neurology·2025

Same author

A clinical perspective on muscle specific kinase antibody positive myasthenia gravis.

Frontiers in immunology·2024

Search research articles

Related Experiment Video

Updated: Jul 16, 2026

Extraction of the EPP Component from the Surface EMG

Extraction of the EPP Component from the Surface EMG

Published on: December 16, 2009

Dok-7 mutations underlie a neuromuscular junction synaptopathy.

David Beeson¹, Osamu Higuchi, Jackie Palace

¹Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK. dbeeson@hammer.imm.ox.ac.uk

Science (New York, N.Y.)

|August 19, 2006

Summary

Recessive mutations in Dok-7 cause congenital myasthenic syndromes (CMSs) leading to proximal muscle weakness due to defective neuromuscular junction structure. This research identifies a key genetic cause for this inherited neuromuscular disorder.

More Related Videos

Proprioception and Tension Receptors in Crab Limbs: Student Laboratory Exercises

Proprioception and Tension Receptors in Crab Limbs: Student Laboratory Exercises

Published on: October 24, 2013

A Mouse Model of Direct Anastomosis via the Prespinal Route for Crossing Nerve Transfer Surgery

A Mouse Model of Direct Anastomosis via the Prespinal Route for Crossing Nerve Transfer Surgery

Published on: October 19, 2021

Related Experiment Videos

Last Updated: Jul 16, 2026

Extraction of the EPP Component from the Surface EMG

Extraction of the EPP Component from the Surface EMG

Published on: December 16, 2009

Proprioception and Tension Receptors in Crab Limbs: Student Laboratory Exercises

Proprioception and Tension Receptors in Crab Limbs: Student Laboratory Exercises

Published on: October 24, 2013

A Mouse Model of Direct Anastomosis via the Prespinal Route for Crossing Nerve Transfer Surgery

A Mouse Model of Direct Anastomosis via the Prespinal Route for Crossing Nerve Transfer Surgery

Published on: October 19, 2021

Area of Science:

Neurology
Genetics
Molecular Biology

Background:

Congenital myasthenic syndromes (CMSs) are inherited neuromuscular disorders.
Characterized by fatigable muscle weakness, CMSs affect neuromuscular transmission.
A subgroup exhibits limb girdle weakness with simplified neuromuscular junctions.

Purpose of the Study:

To investigate the genetic basis of CMS with proximal muscle weakness.
To identify the molecular cause of defective neuromuscular junction structure in a subgroup of CMS patients.

Main Methods:

Genetic analysis of patients with limb girdle CMS.
Investigating mutations in the Dok-7 gene.
Analyzing neuromuscular junction structure and function.

Main Results:

Identified recessive inheritance of Dok-7 mutations in affected individuals.
Dok-7 mutations lead to defective neuromuscular junction structure.
This defect is associated with proximal muscle weakness characteristic of a CMS subgroup.

Conclusions:

Recessive Dok-7 mutations are a significant cause of congenital myasthenic syndromes.
Dok-7 plays a crucial role in neuromuscular junction development and stability.
Understanding Dok-7's role provides insights into neuromuscular transmission disorders.