An Updated Review of Tetrodotoxin and Its Peculiarities

Abstract

Tetrodotoxin (TTX) is a crystalline, weakly basic, colorless organic substance and is one of the most potent marine toxins known. Although TTX was first isolated from pufferfish, it has been found in numerous other marine organisms and a few terrestrial species. Moreover, tetrodotoxication is still an important health problem today, as TTX has no known antidote. TTX poisonings were most commonly reported from Japan, Thailand, and China, but today the risk of TTX poisoning is spreading around the world. Recent studies have shown that TTX-containing fish are being found in other regions of the Pacific and in the Indian Ocean, as well as the Mediterranean Sea. This review aims to summarize pertinent information available to date on the structure, origin, distribution, mechanism of action of TTX and analytical methods used for the detection of TTX, as well as on TTX-containing organisms, symptoms of TTX poisoning, and incidence worldwide.

Local Differences in the Toxin Amount and Composition of Tetrodotoxin and Related Compounds in Pufferfish (Chelonodon patoca) and Toxic Goby (Yongeichthys criniger) Juveniles

“…TTX-bearing organisms have been found in diverse taxa, and the search for the source of the toxin from the interaction of predators, such as pufferfish, and TTX-bearing prey has gradually been revealed [9,[19][20][21]34]. TTX is thought to ultimately accumulate in higher trophic predators, such as pufferfish, through the food web, starting from bacteria [7,8].…”

“…TTX is thought to ultimately accumulate in higher trophic predators, such as pufferfish, through the food web, starting from bacteria [7,8]. On the other hand, the biosynthesis of TTX is understood to be different in TTX-bearing terrestrial animals [9,[35][36][37], because the chemical profiles related to TTX are different between newts and pufferfish [38,39]. The toxic larvae of P. multitentaculata and related species are understood to contribute to the toxification of TTX-bearing fish juveniles, such as those of pufferfish (T. alboplumbeus and C. patoca) and the toxic goby, Y. criniger, as described above [19,21].…”

“…It was considered to be specific to pufferfish until 1964 when its molecular structure was independently reported by three research groups [3][4][5]. This led to the discovery that tarichatoxin of the Californian newt, Taricha torosa, was identical to TTX [6], and since then, the toxin has been detected in a very wide range of taxa [7][8][9]. TTX has also been detected in marine bacterial cultures, suggesting that the toxin is biosynthesized by bacteria and is accumulated in pufferfish through the food chain [7][8][9][10], and an enhanced TTX synthesis by TTX producer bacteria inside their hosts has also been hypothesized [8,11,12].…”

“…This led to the discovery that tarichatoxin of the Californian newt, Taricha torosa, was identical to TTX [6], and since then, the toxin has been detected in a very wide range of taxa [7][8][9]. TTX has also been detected in marine bacterial cultures, suggesting that the toxin is biosynthesized by bacteria and is accumulated in pufferfish through the food chain [7][8][9][10], and an enhanced TTX synthesis by TTX producer bacteria inside their hosts has also been hypothesized [8,11,12]. Indeed, it has been shown that pufferfish remain non-toxic when reared on non-toxic food but are toxified when they ingest TTX-containing feed [13,14].…”

Current Trends and New Challenges in Marine Phycotoxins

“…As a consequence of Na + influx inhibition, neuromuscular complications are features of PSP, which can compromise breathing due to muscle unresponsiveness, leading to paralysis of the diaphragm and resulting in lethality in extremely severe cases [ 88 ]. TTX poisoning presents with similar symptoms, consequently to the shared mode of action [ 8 ]. Toxicity variability among PSTs analogues may result from affinities to VGSCs isoforms [ 89 , 90 ].…”