Tetrodotoxin as a biological defense agent for puffers.

Saitô, Toshio; Noguchi, Tamao; Hashimoto, Kanehisa; Harada, Takuya; Murata, Osamu

doi:10.2331/suisan.51.1175

Cited by 61 publications

(26 citation statements)

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“…A similar result was obtained in oral administration experiments (Kono et al, 2008), suggesting that, under natural conditions as well, pufferfish take up most of the ingested TTX into the liver first. During the ordinary period, some of the TTX taken up into the liver is gradually transferred to the skin, where it accumulates in the basal cells and/or TTX-bearing secretory glands or cells (succiform cells) of the epithelia (Kodama et al, 1986, Tanu et al, 2002, Mahmud et al, 2003a, 2003b, and is excreted by external stimuli under certain circumstances (Kodama et al, 1985, Saito et al, 1985. During the maturation period, the toxin transfer to the skin decreases somewhat, and most of the TTX taken up into the liver would be transported to the ovary, presumably with the precursors of yolk proteins that are synthesized in the liver (Wallace, 1985, Specker andSullivan, 1994).…”

Section: Discussionmentioning

confidence: 99%

Maturation-associated changes in toxicity of the pufferfish Takifugu poecilonotus

Ito

Tatsuno

et al. 2010

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From October 2006 to December 2007, wild specimens of the pufferfish Takifugu poecilonotus (93 females, 45 males) were collected from the Ariake Sea. Tissue toxicity was examined by mouse bioassay, and tetrodotoxin (TTX) content in the blood plasma by enzyme-linked immunosorbent assay. The relationship between toxicity and maturation was investigated based on changes in the gonadosomatic index: December-March in females and November-March in males, the 'maturation period'; April, 'just after spawning'; and the other months, the 'ordinary period'. Toxicity of both sexes was high throughout the year, but sharply declined in April. In all tissues examined (skin, liver, and ovary) other than testis, toxicity exceeded 1000 MU/g or 10,000 MU/individual in many individuals. Seasonal profiles of tissue toxicity differed markedly between sexes. In females, liver toxicity was high during the ordinary period, and ovary toxicity was high during the maturation period. In males, little maturation-associated change in the toxin distribution was observed. Plasma TTX levels were similar between the sexes (1.59-15.1 MU/ml), and fluctuated largely throughout the year without corresponding changes in tissue toxicity. The percentage of TTX binding to high molecular-weight substances in the plasma varied in association with maturation; the binding ratio fluctuated at relatively low levels during the ordinary period, and stabilized at a high level during the maturation period.

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Section: Discussionmentioning

confidence: 99%

Maturation-associated changes in toxicity of the pufferfish Takifugu poecilonotus

Ito

Tatsuno

et al. 2010

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“…Behavioural studies demonstrated that some fish species reject toxic puffer tissues and artificial food pellets containing tetrodotoxin (Yamamori et al . 1980, cited in Saito et al . 1984; Yamamori et al .…”

Section: Natural Deterrentsmentioning

confidence: 99%

Taste preferences in fishes

2003

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The fish gustatory system provides the final sensory evaluation in the feeding process. Unlike other vertebrates, the gustatory system in fish may be divided into two distinct subsystems, oral and extraoral, both of them mediating behavioural responses to food items brought in contact with the fish. The abundance of taste buds is another peculiarity of the fish gustatory system. For many years, morphological and electrophysiological techniques dominated the studies of the fish gustatory system, and systematic investigations of fish taste preferences have only been performed during the last 10 years. In the present review, basic principles in the taste preferences of fish are formulated. Categories or types of taste substances are defined in accordance with their effects on fish feeding behaviour and further mediation by the oral or extraoral taste systems (incitants, suppressants, stimulants, deterrents, enhancers and indifferent substances). Information on taste preferences to different types of substances including classical taste substances, free amino acids, betaine, nucleotides, nucleosides, amines, sugars and other hydrocarbons, organic acids, alcohols and aldehydes, and their mixtures, is summarised. The threshold concentrations for taste substances are discussed, and the relationship between fish taste preferences with fish systematic position and fish ecology is evaluated. Fish taste preferences are highly species‐specific, and the differences among fish species are apparent when comparing the width and composition of spectra for both the stimulants and the deterrents. What is evident is that there is a strong similarity in the taste preferences between geographically isolated fish populations of the same species, and that taste preferences are similar in males and females, although at the individual level, it may vary dramatically among conspecifics. What is noteworthy is that taste responses are more stable and invariable for highly palatable substances than for substances with a low level of palatability. Taste preferences as a function of pH is analysed. There is a good correspondence between development of the gustatory system in fish ontogeny and its ability to discriminate taste properties of food items. There is also a correspondence between oral and extraoral taste preferences for a given species; however, there is no correlation between smell and taste preferences. Taste preferences in fish show low plasticity (in relation to the diet), appear to be determined genetically and seem to be patroclinous. Fish feeding motivation and various environmental factors like water temperature and pollutants such as heavy metals and low pH water may shift fish taste preferences. Comparisons between bioassay and electrophysiological data show that palatability is not synonymous with excitability in the gustatory system. The chemical nature of stimulants and deterrents in various hydrobionts is outlined. The significance of basic knowledge in fish taste preferences for aquaculture and fisheries is emp...

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“…In other cases, fish release secretions that are clearly toxic or deterrent, as in the secretions of boxfish (Ostracion lentiginosus, Ostraciidae; Thomson, 1964), puffers (Tetraodontidae; Saito et aL, 1985), soapfishes (Grammistidae; Randall et al, 1971), soles (Pardachirus pavoninus and P. marmoratus, Soleidae; Clark and George, 1979;Tachibana, 1984), and marine catfish (Arius thallasinus; AI-Hassan etaL, 1987). However, these secretions may serve as alarm pheromones to conspecifics, as well as being predator deterrents.…”

Section: O T H E R P O T E N T I a L A L A R M P H E R O M O N E S Inmentioning

confidence: 99%