Presynaptic phospholipase A2 neurotoxin (PLA2 neurotoxin)

Presynaptic phospholipase A2 (PLA2) neurotoxins, also known as β-neurotoxins, are a major class of toxic enzymes found in the venom of elapid and viperid snakes (UniProt, 2024). These toxins specifically target the presynaptic nerve terminal of the neuromuscular junction, where they bind to specific receptors or membrane components and hydrolyze phospholipids. This enzymatic activity leads to a cascade of events, including an initial surge in neurotransmitter release followed by a profound and often irreversible blockade of synaptic transmission (Rigoni et al., 2005). The resulting clinical manifestation is descending paralysis, which can lead to fatal respiratory failure if untreated. Unlike postsynaptic neurotoxins that bind to receptors, presynaptic PLA2s often cause physical damage to the nerve terminal, making recovery dependent on nerve regeneration (Gutiérrez et al., 2017). Therapeutic strategies focus on the use of antivenoms and small-molecule inhibitors like varespladib, which aim to neutralize the enzymatic activity and prevent further neurological damage (Lewin et al., 2016).

Other names

Beta-neurotoxinβ-neurotoxinPresynaptic PLA2Snake venom phospholipase A2β-PLA2 neurotoxin

Inhibition of the enzymatic hydrolysis of phospholipids at the presynaptic nerve terminal, preventing membrane damage and subsequent blockade of neurotransmitter release (Gutiérrez et al., 2017).