2004 Annual Report 4.What were the most significant accomplishments this past year? D. Progress Report: This report serves to document research conducted under a Reimbursment Cooperative Agreement between ARS and the University Maryland Baltimore County (UMBC). Additional details of the research can be found in the report for the parent project 1950-51000-055-00D, entitled Dietary Effects on Neuronal Signaling. Previous work has shown that exposure to heavy particle irradiation produces neurochemical and cognitive deficits in young animals that are characteristic of much older animals. As a result, it has been suggested that exposure to heavy particles can produce accelerated aging. This year, in collaboration with Dr. Bernie Rabin from UMBC, we assessed the interaction between age and the behavioral effects of exposure to 56Fe particles. The specific hypothesis tested was that lower doses of 56Fe particles would be needed to disrupt performance in older rats than would be needed to disrupt performance in younger rats. Seven- and 17-month old F-344 rats were exposed to 56Fe particles (0, 0.5 or 1.5 Gy, 1 GeV/n) at Brookhaven National Lab and tested for the acquisition of an amphetamine-induced taste aversion (CTA). The threshold for the 56Fe particle-induced disruption of amphetamine-induced CTA learning was lower in the older F-344 rats than in younger S-D rats. On the elevated plus maze, the 7-month old irradiated rats spent significantly less time in the open arm than the non-irradiated controls. Their open arm time was equivalent to that of the non-irradiated 17-month old rats. Exposure to either dose of 56Fe particles did not affect the elevated plus maze performance of the 17-month old rats. In examinations of operant responding, the threshold dose for disruption of this response was significantly lower in the older (7- and 17-month old) F-344 rats than in young S-D rats. We have also shown that tissue taken from young control or irradiated Sprague Dawley rats that had been given strawberry or blueberry supplemented diets was more resistant to oxidative stressors when assessed as a function of disruption of striatal muscarinic receptor sensitivity via hydrogen peroxide exposure in vitro. This is similar to what we described above last year for the aged rats. In this effort a rat brain mini-cDNA library was constructed containing 24 genes that are involved in inflammation, oxidative stress and cell death signaling pathways. Also in the library are three house-keeping genes. These genes will form a panel of indicators for the study of the beneficial effects of BBs on gene regulation in the rat brain or in cell-culture paradigms Review Publications Rabin, B.M., Joseph, J.A., Shukitt Hale, B. 2004. Heavy particle irradiation, neurochemistry and behavior: thresholds, dose-response curves and recovery of function. Advances in Space Research. 33:1330-1333.