TY - JOUR
T1 - Effects of a red-tide toxin on fish hearing
AU - Lu, Z.
AU - Tomchik, S. M.
N1 - Funding Information:
Acknowledgements This work was supported by University of Miami start-up funds and grant R29DC03275 from the National Institute of Deafness and Other Communication Disorders of the National Institute of Health (NIH). It was funded by a Pilot Project Award from grant P30ES05705 of the National Institute of Environmental Health Sciences (NIEHS) of the NIH to the NIEHS Marine and Freshwater Biomedical Sciences Center at the Ro-senstiel School of Marine and Atmospheric Science, University of Miami. We would like to thank Zemin Xu for his participation in initial experiments and Karlisa Callwood for her help in LD50 experiments. Thanks also to Lynne A. Fieber for helpful comments on the manuscript. The animal protocol complies with the Principles of Animal Care, publication No. 86-23, revised 1985 of the NIH, and was approved by the Institutional Animal Care and Use Committees of the University of Miami.
PY - 2002/11/1
Y1 - 2002/11/1
N2 - Red tides are formed from blooms of marine algae. Among them, the dinoflagellate (Karenia brevis) that is responsible for Florida red tides can release many types of natural toxins, which cause massive kills of marine animals, including endangered species, and threaten human health. This study was to investigate whether or not a neurotoxin, brevetoxin-3, purified from Florida red tides affects hearing sensitivity of a teleost fish, the goldfish (Carassius auratus). LD50 of the goldfish that were intraperitoneally injected with brevetoxin-3 was 0.068 μg g-1. Evoked auditory brainstem responses were recorded, and hearing threshold was determined using a correlation method. By comparing thresholds of fish before and after a sublethal-dose injection (0.064 μg g-1) of the toxin, we found that brevetoxin-3 significantly reduces auditory sensitivity up to 9 dB at low frequencies (100 Hz and 500 Hz), but not at a high frequency (2,000 Hz). Reduction of hearing sensitivity was recovered within 24 h. To our knowledge, this is the first study showing a natural red-tide toxin causes minor hearing loss in vertebrates. Results of the study indicate that brevetoxin-3 could affect hearing capabilities of marine animals that survived exposure to red tides. Mechanisms of the toxin-induced reduction of hearing sensitivity are discussed.
AB - Red tides are formed from blooms of marine algae. Among them, the dinoflagellate (Karenia brevis) that is responsible for Florida red tides can release many types of natural toxins, which cause massive kills of marine animals, including endangered species, and threaten human health. This study was to investigate whether or not a neurotoxin, brevetoxin-3, purified from Florida red tides affects hearing sensitivity of a teleost fish, the goldfish (Carassius auratus). LD50 of the goldfish that were intraperitoneally injected with brevetoxin-3 was 0.068 μg g-1. Evoked auditory brainstem responses were recorded, and hearing threshold was determined using a correlation method. By comparing thresholds of fish before and after a sublethal-dose injection (0.064 μg g-1) of the toxin, we found that brevetoxin-3 significantly reduces auditory sensitivity up to 9 dB at low frequencies (100 Hz and 500 Hz), but not at a high frequency (2,000 Hz). Reduction of hearing sensitivity was recovered within 24 h. To our knowledge, this is the first study showing a natural red-tide toxin causes minor hearing loss in vertebrates. Results of the study indicate that brevetoxin-3 could affect hearing capabilities of marine animals that survived exposure to red tides. Mechanisms of the toxin-induced reduction of hearing sensitivity are discussed.
KW - Audiogram
KW - Auditory brainstem response
KW - Brevetoxin
KW - Goldfish
KW - Neurotoxin
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U2 - 10.1007/s00359-002-0369-8
DO - 10.1007/s00359-002-0369-8
M3 - Article
C2 - 12466956
AN - SCOPUS:0036880802
VL - 188
SP - 807
EP - 813
JO - Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology
JF - Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology
SN - 0340-7594
IS - 10
ER -
