Abstract
Pinnatoxins (PnTXs) are emerging neurotoxins that were discovered about 30 years ago. They are solely produced by the marine dinoflagellate Vulcanodinium rugosum, and may be transferred into the food chain, as they have been found in various marine invertebrates, including bivalves. No human intoxication has been reported to date although acute toxicity was induced by PnTxs in rodents. LD50 values have been estimated for the different PnTXs through the oral route. At sublethal doses, all symptoms are reversible, and no neurological sequelae are visible. These symptoms are consistent with impairment of central and peripheral cholinergic network functions. In fact, PnTXs are high-affinity competitive antagonists of nicotinic acetylcholine receptors (nAChRs). Moreover, their lethal effects are consistent with the inhibition of muscle nAChRs, inducing respiratory distress and paralysis. Human intoxication by ingestion of PnTXs could result in various symptoms observed in episodes of poisoning with natural nAChR antagonists. This review updates the available data on PnTX toxicity with a focus on their mode of action on cholinergic networks and suggests the effects that could be extrapolated on human physiology.
Highlights
PnTXs belong to the group of cyclic and macrocyclic imines including about 40 different molecules
These results, together with those obtained on mouse neuromuscular junctions showing that ACh-evoked potentials, miniature end-plate potentials (mEPPs), and end-plate potentials (EPPs) were reduced in amplitude and blocked by Pinnatoxin A (PnTX-A) and PnTX-G in a normal extracellular medium, indicate that PnTXs block the interaction between ACh and its muscle nicotinic acetylcholine receptors (nAChRs) at the endplate [15]
PnTXs are emerging marine biotoxins produced by the dinoflagellate Vulcanodinium rugosum
Summary
The name pinnatoxin (PnTX) originates from Pinna attenuata, a bivalve mollusk from the South. Vulcanodinium rugosum, collected from lagoon water samples in southern France, was identified in 2009 as the sole producer of PnTXs [5] This identification was subsequent to an investigation following an atypical result from the regulatory monitoring of lipophilic toxins in shellfish, showing that mussel extracts from the Ingril lagoon (Mediterranean Sea, France) induced unexpected neurotoxic effects in a mouse bioassay [6]. This observed toxicity was considered unusual and inconsistent with the toxic effects induced by the other known lipophilic toxins [7]. No microalgal species known to produce neurotoxins was observed in the water samples
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