Effects of inhalation of cadmium on the rat olfactory system: behavior and morphology.
Sun J; Miller ML; Hastings L
Neurotoxicol Teratol 1996 Jan; 18(1):89-98
The effects of cadmium (7440439) on the olfactory system were studied in rats. Adult male Long-Evans-rats whose olfactory thresholds had been previously determined using a conditioned suppression paradigm utilizing ethyl-acetate as the odorant and footshock as the aversive stimulus inhaled cadmium-oxide (1306190) aerosols at nominal concentrations of 0, 250, or 500 micrograms per cubic meter 5 hours daily 5 days a week for up to 20 weeks (wk) in two experiments. The effects of cadmium on olfaction were assessed by remeasuring the odor thresholds after 5, 10, 15, or 20wk of exposure. To evaluate a possible delayed effect of cadmium on olfaction some rats were tested for their ability to find buried food immediately and 6 months (mo) after exposure ended in the second experiment. Selected rats were euthanized after 5, 10, 15, or 20wk of exposure and the olfactory bulb and epithelium, heart, lungs, brain, and kidneys were analyzed for cadmium in experiment one. These tissues were examined for histopathological changes in the second experiment. Cadmium did not induce anosmia or alter the olfactory thresholds in any experiment. All tested rats were able to find the buried food within 1 minute 6mo after cadmium exposure ended. Cadmium accumulated in all tissues in a dose dependent manner and in the olfactory bulb and kidneys in a time dependent manner as well. Cadmium did not cause any histopathological changes in the olfactory and nasal tissues. Cadmium induced mild tubular degeneration in the kidneys, slight fibrotic changes in the walls of terminal bronchioles in the lungs, and moderate to pronounced degenerative cardiomyopathy in the heart. The authors conclude that cadmium does not appear to cause olfactory damage in rats despite its accumulating in the olfactory system. The failure of cadmium to cause olfactory dysfunction could reflect the protective effects of metallothionein, which is induced in cadmium exposed tissues, or the highly resilient nature of the rodent olfactory system.
Cadmium-compounds; In-vivo-studies; Laboratory-animals; Inhalation-studies; Nasal-cavity; Odor-threshold; Behavioral-testing; Neurotoxicity; Neurotoxic-effects; Histopathology; Tissue-distribution; Dose-response
Environmental Health University of Cincinnati 3223 Eden Avenue Cincinnati, Ohio 45267
Neurotoxic Disorders; Neurotoxic-effects
Neurotoxicology and Teratology
University of Cincinnati, Cincinnati, Ohio