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THE USE OF THE ELEVATED PLUS MAZE IN THE TOXICOLOGY LABORAOTRY: PILOT STUDIES AND ASSESSMENT OF ANXIETY IN RATS EXPOSED TO LEAD ACETATE OR SUB-CHRONIC LEVELS OF TOLUENE.
Citation:
OSHIRO, W. M. AND P. J. BUSHNELL. THE USE OF THE ELEVATED PLUS MAZE IN THE TOXICOLOGY LABORAOTRY: PILOT STUDIES AND ASSESSMENT OF ANXIETY IN RATS EXPOSED TO LEAD ACETATE OR SUB-CHRONIC LEVELS OF TOLUENE. Presented at Behavioral Toxicology Society, Little Rock, AR, September 15 - 19, 2006.
Description:
A common complaint of individuals exposed to neurotoxic agents is increased anxiety.
Rat models of the effects of long-term exposure to environmental chemicals on anxiety
are lacking. The elevated plus-maze (EPM) is a widely used tool in the search for new
anxiolytic compounds and has been validated as a convenient method for determining the
existence of anxiolytic or anxiogenic action of drugs in both mice and rats. Although this
method has been validated extensively it has also been shown to be extremely sensitive to
testing conditions, handling experience, noise, and previous maze experience. Hence, we
conducted a series of pilot studies to 1) establish baseline EPM measures in a
neurobehavioral toxicology laboratory, 2) validate pharmacologically the effects of
known anxiolytic and anxiogenic drugs, 3) assess the effects of single vs. group-housed
animals and 4) assess the usefulness of repeated testing on the EPM. In addition,
assessments of anxiety were conducted in two separate studies of rats exposed to
environmentally relevant chemicals. In the first study, we tested rats exposed to 0 or
0.2% Pb acetate in drinking water, either during gestation (GD16 - 20), after birth
(PND1 - 21), or both. No behavioral differences were seen when animals were tested on
the EPM beginning on PND103. In the second study, we tested adult rats that had been
exposed to toluene (0, 10, 100, and 1000 ppm) through inhalation 6 h/day, 5 d/week, for
13 weeks prior to EPM testing. Half of these animals were tested for motor activity in
figure-eight mazes prior to EPM testing. No differences in anxiety measures were
observed among the toluene-exposure groups; however, a significant reduction in the
percent of open arm entrances and open arm time was found in the rats tested in a figure-
eight maze prior to tests on the EPM. This abstract does not reflect EPA policy.