scholarly journals Presynaptic Paraneoplastic Disorders of the Neuromuscular Junction: An Update

2021 ◽  
Vol 11 (8) ◽  
pp. 1035
Author(s):  
Maria Pia Giannoccaro ◽  
Patrizia Avoni ◽  
Rocco Liguori
Keyword(s):  
Potassium Channels ◽  
Neuromuscular Junction ◽  
Calcium Channels ◽  
Myasthenia Gravis ◽  
Neuromuscular Transmission ◽  
Voltage Gated ◽  
Voltage Gated Calcium Channels ◽  
Immune Mediated ◽  
Recent Developments ◽  
Myasthenic Syndrome

The neuromuscular junction (NMJ) is the target of a variety of immune-mediated disorders, usually classified as presynaptic and postsynaptic, according to the site of the antigenic target and consequently of the neuromuscular transmission alteration. Although less common than the classical autoimmune postsynaptic myasthenia gravis, presynaptic disorders are important to recognize due to the frequent association with cancer. Lambert Eaton myasthenic syndrome is due to a presynaptic failure to release acetylcholine, caused by antibodies to the presynaptic voltage-gated calcium channels. Acquired neuromyotonia is a condition characterized by nerve hyperexcitability often due to the presence of antibodies against proteins associated with voltage-gated potassium channels. This review will focus on the recent developments in the autoimmune presynaptic disorders of the NMJ.

Lambert-Eaton Myasthenia Syndrome

2013 ◽  
Author(s):  
Aaron E. Miller ◽  
Teresa M. DeAngelis
Keyword(s):  
Neuromuscular Junction ◽  
Calcium Channels ◽  
Clinical Features ◽  
Presynaptic Membrane ◽  
Tumor Removal ◽  
Management Options ◽  
Voltage Gated ◽  
Voltage Gated Calcium Channels ◽  
Severe Weakness

Lambert-Eaton myasthenia syndrome (LEMS) is an autoimmune-mediated disorder of the neuromuscular junction, which involves autoantibodies to voltage-gated calcium channels on the presynaptic membrane. In this chapter, we discuss the characteristic clinical features of LEMS, its electrophysiological distinction from MG, as well as its paraneoplastic presentation. We also review the immunotherapeutic management options in cases with severe weakness and those refractory to tumor removal.

Interaction of synaptotagmin with voltage gated calcium channels: A role in Lambert-Eaton myasthenic syndrome?

1993 ◽  
Vol 3 (5-6) ◽  
pp. 451-454 ◽  
Author(s):  
Pascale David ◽  
Nicole Martin-Moutot ◽  
Christian Leveque ◽  
Oussama El Far ◽  
Masami Takahashi ◽  
...  
Keyword(s):  
Calcium Channels ◽  
Voltage Gated ◽  
Voltage Gated Calcium Channels ◽  
Myasthenic Syndrome

scholarly journals Impact of calcium-activated potassium channels on NMDA spikes in cortical layer 5 pyramidal neurons

2016 ◽  
Vol 115 (3) ◽  
pp. 1740-1748 ◽  
Author(s):  
Tobias Bock ◽  
Greg J. Stuart
Keyword(s):  
Potassium Channels ◽  
Calcium Channels ◽  
Pyramidal Neurons ◽  
Cortical Layer ◽  
Sk Channels ◽  
Spike Generation ◽  
Voltage Gated ◽  
Voltage Gated Calcium Channels ◽  
Basal Dendrites ◽  
Calcium Activated Potassium Channels

Active electrical events play an important role in shaping signal processing in dendrites. As these events are usually associated with an increase in intracellular calcium, they are likely to be under the control of calcium-activated potassium channels. Here, we investigate the impact of calcium-activated potassium channels on N-methyl-d-aspartate (NMDA) receptor-dependent spikes, or NMDA spikes, evoked by glutamate iontophoresis onto basal dendrites of cortical layer 5 pyramidal neurons. We found that small-conductance calcium-activated potassium channels (SK channels) act to reduce NMDA spike amplitude but at the same time, also decrease the iontophoretic current required for their generation. This SK-mediated decrease in NMDA spike threshold was dependent on R-type voltage-gated calcium channels and indicates a counterintuitive, excitatory effect of SK channels on NMDA spike generation, whereas the capacity of SK channels to suppress NMDA spike amplitude is in line with the expected inhibitory action of potassium channels on dendritic excitability. Large-conductance calcium-activated potassium channels had no significant impact on NMDA spikes, indicating that these channels are either absent from basal dendrites or not activated by NMDA spikes. These experiments reveal complex and opposing interactions among NMDA receptors, SK channels, and voltage-gated calcium channels in basal dendrites of cortical layer 5 pyramidal neurons during NMDA spike generation, which are likely to play an important role in regulating the way these neurons integrate the thousands of synaptic inputs they receive.

Immune-Mediated Disease of the Neuromuscular Junction

2019 ◽  
pp. 130-176
Author(s):  
Robert P. Lisak ◽  
James Selwa
Keyword(s):  
Neuromuscular Junction ◽  
Myasthenia Gravis ◽  
Rare Disease ◽  
Treatment Options ◽  
Clinical Manifestations ◽  
Diagnosis And Treatment ◽  
Future Directions ◽  
Immune Mediated ◽  
Myasthenic Syndrome

The chapter is concerned with disorders that affect the neuromuscular junction (NMJ). Myasthenia gravis (MG) is a prototypic antibody-mediated disease affecting the neuromuscular junction. The chapter looks at the epidemiology of MG. It also considers clinical manifestations and presentations, classification and staging, and diagnosis. The chapter also examines immunologic testing and issues such as pregnancy in MG. It considers future directions and treatment options in this area. Next, the chapter considers Lambert Eaton myasthenic syndrome (LEMS), which is a rare disease of the NMJ that is difficult to diagnose. The chapter looks at clinical manifestations, diagnosis, and treatment. Finally, the chapter briefly considers other immune-mediated diseases.

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