title: Florida Red Tide: Inhalation Toxicity ofKarenia brevisExtract in Rats.
abstract: Brevetoxins are neurotoxins produced by the marine dinoflagellateKarenia brevis.Histopathologic examination of marine mammals dying following repeated exposure of brevetoxins during red tide events suggests that the respiratory tract, nervous, hematopoietic, and immune systems are potential targets for toxicity in repeatedly exposed individuals. The purpose of this experiment was to evaluate the effects of repeated inhalation ofK. brevisextract on these potential target systems in rats. Male Sprague-Dawley rats were exposed four hours/day, five days/week for up to four weeks to target concentrations of 200 and 1000 μg/LK. brevisextract (approximately 50 and 200 μg/L brevetoxin-like compounds; positive neurotoxicity in a fish bioassay). Control rats were sham exposed to air. Immunohistochemical staining of pulmonary macrophages indicated deposition of brevetoxin-like compound within the lung. However, exposure resulted in no clinical signs of toxicity or behavioral changes. There were no adverse effects on hematology or serum chemistry. No histopathological changes were observed in the nose, lung, liver, kidneys, lymph nodes, spleen, or brain of exposed rats. Immune suppression was suggested by reduced responses of spleen cells in the IgM-specific antibody-forming plaque cell response assay and reduced responses of lymphocytes to mitogen stimulationin vitro.Differences between responses observed in rats in this study and those observed in manatees may be a function of dose or species differences in sensitivity.
authors.affiliation: Lovelace Respiratory Research Institute, Albuquerque, NM, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Benson
authors.affiliation: University of Georgia, Athens, GA, USA.
authors.forename: F F
authors.initials: FF
authors.lastname: Hahn
authors.affiliation: Center for Marine Science, University of North Carolina at Wilmington, NC USA.
authors.forename: B M
authors.initials: BM
authors.lastname: Tibbetts
authors.affiliation: University of Miami, Miami, FL, USA.
authors.forename: L E
authors.initials: LE
authors.lastname: Bowen
authors.forename: T F
authors.initials: TF
authors.lastname: March
authors.forename: R J
authors.initials: RJ
authors.lastname: Langley
authors.forename: T F
authors.initials: TF
authors.lastname: Murray
authors.forename: A J
authors.initials: AJ
authors.lastname: Bourdelais
authors.forename: J
authors.initials: J
authors.lastname: Naar
authors.forename: J
authors.initials: J
authors.lastname: Zaias
authors.forename: D G
authors.initials: DG
authors.lastname: Baden