neurotoxins

Neurotoxins are substances that disrupt the structure or function of the nervous system. They can be biological toxins produced by organisms such as bacteria, plants, and animals; synthetic chemicals; or naturally occurring environmental contaminants capable of affecting neurons or neural networks.

They act through diverse mechanisms, including blocking or modifying ion channels, inhibiting neurotransmitter release, altering receptor activity, or interfering with enzymes involved in neural signaling. The specific effect depends on the toxin and the neural target.

Examples include botulinum toxin, which prevents acetylcholine release at neuromuscular junctions; tetrodotoxin and saxitoxin that block voltage-gated sodium channels; conotoxins that target neural ion channels; and plant alkaloids such as aconitine that alter channel function. Organophosphate nerve agents and pesticides inhibit acetylcholinesterase, causing excessive acetylcholine signaling. Heavy metals such as lead, mercury, arsenic, and manganese can cause neurodevelopmental and neurobehavioral deficits with both acute and chronic exposure.

Exposure occurs via ingestion, inhalation, or dermal contact and can lead to a range of symptoms from numbness and weakness to seizures, coma, or respiratory failure. In children and developing fetuses, neurotoxins can cause long-lasting cognitive and motor impairments.

Diagnosis and treatment depend on the toxin. General management emphasizes decontamination and supportive care. Specific antidotes or therapies may be available, for example antitoxins for botulism, atropine and oximes for organophosphate poisoning, and chelation for certain heavy metals. Public health measures and safety regulations aim to limit exposure and monitor environmental and occupational risks.

While the term encompasses many substances, neurotoxins are studied to understand nervous-system vulnerabilities and to develop medical countermeasures, diagnostics, and therapies for toxin-related illnesses.