PUBLICATION

Morphological abnormalities and sensorimotor deficits in larval fish exposed to dissolved saxitoxin

Authors
Lefebvre, K.A., Trainer, V.L., and Scholz, N.L.
ID
ZDB-PUB-040329-3
Date
2004
Source
Aquatic toxicology (Amsterdam, Netherlands)   66(2): 159-170 (Journal)
Registered Authors
Scholz, Nat
Keywords
axitoxin, Algal toxin, Zebrafish, Danio rerio, Fish, Harmful algal bloom, Paralytic shellfish poisoning, PSP, Neurotoxin
MeSH Terms
  • Animals
  • Biological Availability
  • Eye/pathology
  • Larva/drug effects
  • Larva/metabolism
  • Motor Activity/drug effects*
  • Paralysis/chemically induced*
  • Pericardium/pathology
  • Saxitoxin/pharmacokinetics*
  • Saxitoxin/toxicity*
  • Toxicity Tests
  • Yolk Sac/pathology
  • Zebrafish/anatomy & histology
  • Zebrafish/metabolism*
PubMed
15036871 Full text @ Aquat. Toxicol.
Abstract
The dietary uptake of one suite of dinoflagellate-produced neurotoxins, that are commonly called paralytic shellfish poisoning (PSP) toxins, is known to cause acute fish kills. However, little is known about the effects of dissolved phase exposure and the potential sublethal effects of this route of exposure on early developmental stages of fish. Toxin exposure during early development is of particular concern because the embryos and larvae of some marine fish species may be unable to actively avoid the dissolved toxins that algal cells release into the water column during harmful algal blooms. Here we use the zebrafish (Danio rerio) as a model experimental system to explore the sublethal effects of a dissolved PSP toxin, saxitoxin (STX), on early development in fish, including sensorimotor function, morphology, and long-term growth and survival. Aqueous phase exposures of [Formula: see text] microg STX eq.l(-1) caused reductions in sensorimotor function as early as 48h postfertilization (hpf) and paralysis in all larvae by 4 days postfertilization (dpf). Rohon-Beard mechanosensory neurons appeared to be more sensitive to STX than dorsal root ganglion neurons at this dose. Additionally, exposure to [Formula: see text] microg STX eq.l(-1) resulted in severe edema of the eye, pericardium, and yolk sac in all exposed larvae by 6dpf. The onset of paralysis in STX-exposed larvae was stage-specific, with older larvae becoming paralyzed more quickly than younger larvae (5h at 6dpf as compared to 8 and 46h for 4 and 2dpf larvae, respectively). When transferred to clean water, many larvae recovered from the morphological and sensorimotor effects of STX. Thus, the sublethal effects of the toxin on larval morphology and behavior were reversible. However, zebrafish exposed to STX transiently during larval development (from 2 to 4dpf) had significantly reduced growth and survival at 18 and 30 days of age. Collectively, these data show that (1) dissolved phase STX is bioavailable to fish embryos and larvae, (2) the toxin is a paralytic with potencies that are stage-specific for fish larvae, (3) the observed toxicological effects of STX exposure are reversible, and (4) a short-term toxin exposure can negatively impact the survival of fish several weeks later. Dissolved algal toxins may therefore have important sublethal effects on vulnerable species of fish.
Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping