Here we examine the actions of six snake neurotoxins (alpha-cobratoxin from Naja 
naja siamensis, erabutoxin-a and b from Laticauda semifasciata; CM12 from N. 
haje annulifera, toxin III 4 from Notechis scutatus and a long toxin from N. 
haje) on nicotinic acetylcholine receptors in the cercal afferent, giant 
interneuron 2 synapse of the cockroach, Periplaneta americana. All toxins tested 
reduced responses to directly-applied ACh as well as EPSPs evoked by electrical 
stimulation of nerve XI with similar time courses, suggesting that their action 
is postsynaptic. Thus, these nicotinic receptors in a well-characterized insect 
synapse are sensitive to both long and short chain neurotoxins. This 
considerably expands the range of snake toxins that block insect nicotinic 
acetylcholine receptors and may enable further pharmacological distinctions 
between nAChR subtypes.