Beta-Bungarotoxin (bBTX)

β-Bungarotoxin is a form of bungarotoxin that is fairly common in Krait venoms. The target of this neurotoxin is at the presynaptic terminal, where it blocks release of acetylcholine. There are two isoforms, β1-bungarotoxin and β2-bungarotoxin. It has phospholipase A2 activity. The snake venom phospholipase A2 neurotoxin, beta-bungarotoxin, acts presynaptically to alter acetylcholine release in both the peripheral and central nervous systems. Beta-bungarotoxin inhibited phosphorylation of synapsin I, GAP-43 and MARCKS in rat brain synaptosomes. This inhibition was not due to the inhibition of ATP synthesis, action of arachidonic acid metabolites, or stimulation of phosphatase activities. Furthermore, the activities of Ca2+/calmodulin-kinase II, cAMP-kinase and protein kinase C were not altered by beta-bungarotoxin in either synaptic plasma membranes or cytosol.