Binds with high affinity to muscular (tested on Torpedo marmorata, Kd=0.4 nM) and neuronal (tested on chimeric alpha-7/CHRNA7, Kd=0.95 nM) nicotinic acetylcholine receptor (nAChR) and inhibits acetylcholine from binding to the receptor, thereby impairing neuromuscular and neuronal transmission. It also shows an activity on GABA(A) receptors. It antagonises GABA-activated currents with high potency when tested on primary hippocampal neurons. It inhibits recombinantly expressed GABA(A) receptors composed of alpha-2-beta-2-gamma-2 (GABRA2-GABRB2-GABRG2) subunits with high potency (62.3% inhibition at 20 uM of toxin). It also shows a weaker inhibition on GABA(A) receptors composed of alpha-1-beta-2-gamma-2 (GABRA1-GABRB2-GABRG2) subunits, alpha-4-beta-2-gamma-2 (GABRA4-GABRB2-GABRG2) subunits, and alpha-5-beta-2-gamma-2 (GABRA5-GABRB2-GABRG2) subunits. A very weak inhibition is also observed on GABA(A) receptor composed of alpha-1-beta-3-gamma-2 (GABRA1-GABRB3-GABRG2). It has also been shown to bind and inhibit recombinant GABA(A) receptor beta-3/GABRB3 subunit (Kd=about 50 nM). In addition, it blocks the extracellular increase of dopamine evoked by nicotine only at the higher dose (4.2 uM). In vivo, when intraperitoneally injected into mice, induces flaccid paralysis of the limbs and respiratory distress, and causes death in a dose-dependent manner (PubMed:14505938). Monomer in solution, homodimer in crystal state. Expressed by the venom gland. LD(50) is 230 ug/kg by intraperitoneal injection into mice. Is identical to Alpha-bungarotoxin (A31) from B.multicinctus (AC P60615). Belongs to the snake three-finger toxin family. Long-chain subfamily. Type II alpha-neurotoxin sub-subfamily.