Diseases of the neuromuscular junction (NMJ) include a large spectrum of
acquired and inherited disorders mainly characterized by fluctuating muscle
weakness and fatigability of ocular, bulbar or limb muscles. Remarkable
progress has been made in our understanding of the pathogenesis of these
disorders in recent years.
The expression and localization of the proline-rich membrane anchor
(PRiMA), an anchoring protein of tetrameric globular form acetylcholines-terase (G4
AChE), were studied at vertebrate neuromuscular junctions.
Both muscle and motor neuron contributed to this synaptic expression
pattern. During the development of rat muscles, the expression of PRiMA
and AChET and the enzymatic activity increased dramatically; however,
the proportion of G4AChE decreased.
Nicotinic acetylcholine receptors, or nAChRs, are cholinergic receptors that form ligand-gated ion channels in the plasma membranes of certain neurons and on the postsynaptic side of the neuromuscular junction . Being ionotropic receptors, nAChRs are directly linked to an ion channel and do not make use of a second messenger as metabotropic receptors do.
Pompilidotoxins (PMTXs,a and b) are small peptides consisting of 13
amino acids purified from the venom of the solitary waspsAnoplius samari-ensis(a-PMTX) and Batozonellus maculifrons(b-PMTX). They are known
to facilitate synaptic transmission in the lobster neuromuscular junction,
and to slow sodium channel inactivation.