Snake venoms and the neuromuscular junction

There are approximately 420 venomous species of snakes living on the earth. Their venoms, each unique, can affect multiple organ systems. The venoms have a predilection for the peripheral nervous system where the neuromuscular junction is a favorite target. Those venoms affecting the release of acetylcholine from the presynaptic membrane are called beta-neurotoxins and those affecting the postsynaptic membrane are called alpha-neurotoxins. alpha-Bungarotoxin has been used in quantitative studies of acetylcholine receptor density and turnover and for the assay of antibodies directed against the acetylcholine receptor. A unique feature of timber rattlesnake venom is its ability to cause clinical myokymia. This likely results from a blockade of voltage gated K+ antibodies.