Aconite (Aconitum napellus) poisoning causes rapid death primarily by which mechanism?
- A Irreversible inhibition of acetylcholinesterase causing cholinergic crisis
- B Competitive antagonism of nicotinic acetylcholine receptors causing flaccid paralysis
- C Persistent activation of voltage-gated sodium channels causing depolarisation block of nerve and cardiac muscle ✓
- D Inhibition of mitochondrial complex I causing cellular energy failure
Correct answer: C. Persistent activation of voltage-gated sodium channels causing depolarisation block of nerve and cardiac muscle
Explanation
Aconitine binds to the voltage-gated sodium channel and holds it in the open-activated state, preventing inactivation. This produces persistent membrane depolarisation leading to paraesthesia, severe ventricular arrhythmias (VF, VT), and cardiovascular collapse. Death is primarily cardiac. Unlike organophosphates (AChE inhibition), curare-like agents (nicotinic blockade), or cyanide (complex inhibition), aconitine's target is the Nav channel — a unique and testable mechanism.
Reference: The Essentials of Forensic Medicine and Toxicology (Narayan Reddy), 34th ed.
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