Α-bungarotoxin

Α-bungarotoxin is a form of neurotoxin that is produced by the Bungarus multicinctus, commonly known as the many-banded krait. This toxin is a type of Elapid snake venom, which is characterized by its high toxicity and rapid onset of effects.

Structure and Function

Α-bungarotoxin is a protein composed of 74 amino acids and has a molecular weight of approximately 8,000 daltons. It is a member of the three-finger toxin family, named for the three protruding loops that form a characteristic structure. The toxin binds irreversibly to nicotinic acetylcholine receptors (nAChRs) at the neuromuscular junction, blocking the action of acetylcholine and leading to muscle paralysis.

Mechanism of Action

The toxin works by binding to the α-subunit of the nAChR, preventing the binding of acetylcholine and thus inhibiting the ion channel function of the receptor. This results in a blockage of nerve impulses at the neuromuscular junction, leading to flaccid paralysis and potentially death due to respiratory failure.

Clinical Significance

Α-bungarotoxin is of significant interest in the field of neuroscience due to its ability to selectively bind to nAChRs. This has led to its use as a tool in the study of these receptors, and it has been instrumental in the discovery and characterization of the various subtypes of nAChRs. In addition, the toxin's mechanism of action has provided insights into the workings of the neuromuscular junction and the process of synaptic transmission.

Toxicity and Treatment

The toxicity of α-bungarotoxin is high, with a lethal dose in mice being approximately 0.1 μg/kg. Symptoms of envenomation by the many-banded krait can include abdominal pain, vomiting, and progressive paralysis. Treatment involves the administration of antivenom, along with supportive care such as mechanical ventilation to manage respiratory failure. Template:Toxin-stub

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