Myasthenia gravis (MG) is an autoimmune disease resulting in destruction of the post-synaptic nicotinic receptors at the neuromuscular junction. Classically, the earliest symptoms of MG are ocular, including ptosis and diplopia. Other less common early symptoms include dysphagia and fatigable chewing. Our case report describes the unusual presentation of MG in a teenager patient and presented f...

In the neuromuscular junction, postsynaptic nicotinic acetylcholine receptor (nAChR) clustering, trans-synaptic communication and synaptic stabilization are modulated by the molecular mechanisms underlying synaptic plasticity. The synaptic functions are based presynaptically on the active zone architecture, synaptic vesicle proteins, Ca2+ channels and synaptic vesicle recycling. Postsynapticall...

The existence of nicotinic acetylcholine receptors (AChRs) on the motor nerve terminals of vertebrates has long been controversial. We have re-examined this issue by electron microscope autoradiography with [125I] alpha-bungarotoxin, following separation of nerve terminals from muscle fibers by collagenase and protease treatment. We found no label over nerve terminal membranes other than that d...

The agonist-binding site of nicotinic acetylcholine receptors (nAChRs) spans an interface between two subunits of the pentameric receptor. The principal component of this binding site is contributed by an α subunit, and it binds the cationic moiety of the nicotinic pharmacophore. The other part of the pharmacophore, a hydrogen bond acceptor, has recently been shown to bind to the complementary ...

A blocker of postsynaptic acetylcholine receptors was isolated from venom of the Eastern green mamba Dendroaspis angusticeps, by gel filtration, ion-exchange and reverse phase high performance liquid chromatography. The isolated component blocks neuromuscular transmission and responses to exogenously applied acetylcholine in isolated chick biventer cervices preparations. These results suggest t...

We show that miR-1, a conserved muscle-specific microRNA, regulates aspects of both pre- and postsynaptic function at C. elegans neuromuscular junctions. miR-1 regulates the expression level of two nicotinic acetylcholine receptor (nAChR) subunits (UNC-29 and UNC-63), thereby altering muscle sensitivity to acetylcholine (ACh). miR-1 also regulates the muscle transcription factor MEF-2, which re...

Agrin induces the formation of highly localized specializations on myotubes at which nicotinic acetylcholine receptors (AChRs) and many other components of the postsynaptic apparatus at the vertebrate skeletal neuromuscular junction accumulate. Agrin also induces AChR tyrosine phosphorylation. Treatments that inhibit tyrosine phosphorylation prevent AChR aggregation. To examine further the rela...

We examined the effects of motor-nerve stimulation on the intracellular Ca2+ levels of Schwann cells, the glial cells at the frog neuromuscular junction. Schwann cells, which were loaded with the fluorescent Ca2+ indicator fluo-3 and examined by confocal microscopy, showed a transient increase in free Ca2+ within a few seconds of the onset of tetanic stimulation of the motor nerve. The Ca2+ res...

BACKGROUND Myasthenia gravis is a disorder of neuromuscular transmission associated with autoantibodies against the nicotinic acetylcholine receptor. We have previously developed a customized protein macroarray comprising 1827 potential human autoantigens, which permitted to discriminate sera of patients with different cancers from sera of healthy controls, but has not yet been evaluated in ant...