Fig. 1.

General experimental timeline. Day 0 represents the day of arrival of each batch of animals at the University of South Carolina School of Medicine vivarium. Handling and habituation of the rats began the following day. After one week, animals were assigned to either the c-Fos expression or in vivo microdialysis experimental groups. For the c-Fos experiments animals received a week of daily habituation to intranasal saline. On the test day (Day 15) each rat received intranasal OxA or saline and was euthanized 2 hr later. Processing of brain tissue, immunohistochemistry, cell counts and data analysis began on Day 16 and proceeded until complete for each batch of rats used for c-Fos analysis. For the in vivo microdialysis experiments, guide cannula surgery was performed during Days 8–10. After several days of recovery, animals received a week of daily habituation to intranasal saline. The first microdialysis session was performed on Day 19 and the second session on Day 21. Half of the rats received OxA in the first session and saline in the second session; the order was reversed for the other half of the rats. On the day following the second microdialysis session (Day 22) the rats were euthanized, their brains processed for histochemical verification of probe placement, and HPLC analysis of dialysate samples began.