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Chinook salmon (Oncorhynchus tshawytscha) and rainbow trout (Oncorhynchus mykiss) exposed to copper: Neurophysiological and histological effects on the olfactory system
Author(s) -
Hansen James A.,
Rose James D.,
Jenkins Robert A.,
Gerow Kenneth G.,
Bergman Harold L.
Publication year - 1999
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620180917
Subject(s) - rainbow trout , chinook wind , oncorhynchus , olfactory bulb , biology , trout , olfactory system , olfaction , salmonidae , anatomy , zoology , fishery , endocrinology , ecology , central nervous system , fish <actinopterygii> , neuroscience
Olfactory epithelial structure and olfactory bulb neurophysiological responses were measured in chinook salmon and rainbow trout in response to 25 to 300 μg copper (Cu)/L. Using confocal laser scanning microscopy, the number of olfactory receptors was significantly reduced in chinook salmon exposed to ≥0 μg Cu/L and in rainbow trout exposed to ≥200 μg Cu/L for 1 h. The number of receptors was significantly reduced in both species following exposure to 25 μg Cu/L for 4 h. Transmission electron microscopy of olfactory epithelial tissue indicated that the loss of receptors was from cellular necrosis. Olfactory bulb electroencephalogram (EEG) responses to 10 −3 M L‐serine were initially reduced by all Cu concentrations but were virtually eliminated in chinook salmon exposed to ≥50 μg Cu/L and in rainbow trout exposed to ≥200 μg Cu/L within 1 h of exposure. Following Cu exposure, EEG response recovery rates were slower in fish exposed to higher Cu concentrations. The higher sensitivity of the chinook salmon olfactory system to Cu‐induced histological damage and neurophysiological impairment parallels the relative species sensitivity observed in behavioral avoidance experiments. This difference in species sensitivity may reduce the survival and reproductive potential of chinook salmon compared with that of rainbow trout in Cu‐contaminated waters.