Substantial evidence suggests that serotonin (5-HT) activation within the brain modulates anxiety-like behavior. The bed nucleus of the stria terminalis (BNST) has been argued to mediate anxiety-like behavioral responding, and the activation of 5-HT systems may modulate anxiety-like behavior via the release of 5-HT within the BNST. Prior studies have suggested that the 5-HT1, 7 agonist 5-carboxyamidotrytamine (5-CT) is anxiolytic, which is consistent with a reduction in BNST activity via the activation of postsynaptic 5- HT1A receptors. However the anxiolytic effects of 5-CT could also have been mediated by 5-HT7 receptor activation. Hence, to isolate the effects of 5-HT1A on anxiety-like behavior, we infused the 5-HT1A antagonist WAY-100635 (0, 0.04, 0.4, and 4.0 μg/μl in saline vehicle) into the BNST of rats immediately before social interaction or acoustic startle testing. For social interaction testing pairs of rats were administered two 5-sec 1- mA footshocks immediately after infusion, removed from the chamber and measured for social interaction in a separate testing apparatus. For acoustic startle testing, rats were placed in boxes and measured for the percentage increase in test (post-infusion) startle from baseline (pre-infusion) startle. Anxiety levels were operationalized as the amount of social interaction per line cross and the percentage increase in startle following drug infusion. WAY-100635 dose dependently decreased social interaction, indicative of an anxiogenic effect. Interestingly, 0.4μg/μl of WAY-100635 decreased startle, indicative of an anxiolytic effect. These data suggest that activation of the 5-HT systems modulates anxiety-like behavior by altering activity within the BNST.
| Identifer | oai:union.ndltd.org:uvm.edu/oai:scholarworks.uvm.edu:graddis-1191 |
| Date | 06 October 2008 |
| Creators | Rhodes, Kimberly |
| Publisher | ScholarWorks @ UVM |
| Source Sets | University of Vermont |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Graduate College Dissertations and Theses |
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