Behaniroal alteration on rats of following exposure to prenatal gamma-ray irradiation

Research Project

Project/Area Number	04610048
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	Psychology
Research Institution	Shinshu University
Principal Investigator	TAMAKI Yoshitaka Shinshu Univ., Faculty of Education professor, 教育学部, 教授 (50090428)
Co-Investigator(Kenkyū-buntansha)	INOUYE Minoru Nagoya Univ., The Research Institute of Environmental Medicine Associate Profess, 環境医学研究所, 助教授 (20090425)
Project Period (FY)	1992 – 1993
Project Status	Completed (Fiscal Year 1993)
Budget Amount *help	¥1,200,000 (Direct Cost: ¥1,200,000) Fiscal Year 1993: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 1992: ¥700,000 (Direct Cost: ¥700,000)
Keywords	Prenatal lrradiation / Gamma-ray / Behavioral alteration / Sidman avoidance schedule / Olton maze / 初期行動発達
Research Abstract	The present experiments were designed to examine the behavioral alterations on rats following exposure to prenatal gamma-ray radiation. Female Fischer344 rats (F334/Du Crj) were exposed to gamma-ray radiation of 0.27, 0.48, 1.46 Gy on day 15 of gestation. Experiment 1 : when the male offspring from control and irradiated dams matured, they were trained with a Sidman (free-operant) avoidance schedule in a running wheel for 40 consecutive days. If the animal did not rotate the wheel at least a half turn, a brief shock (0.2 sec) was delivered to grids of the wheel every 5 sec. Each wheel turning response postponed the next shock for 20 sec. No reliable differences were observed in the rate of shock received. However, rats exposed to 1.46 Gy responded at a higher response rate during the early training sessions. In the 1.46 Gy irradiation, changes in the overall rate of responding results in a shift toward shorter interresponse times, because of no substantial decrease in the number of shoc … More k received. Exeriment 2 : When the other male offspring from control and irradiated dams matured, they were trained to obtain single food pellets Placed at the end of each arm of the Olton maze. All groups rapidly acquired the task. Rats exposed to 1.46 Gy, however, entered previously chosen arms more often than control and other irradiated groups. One possibility which can be offered to this finding is that an increase in memory seems to load at choosing the different arms adversely affect retention of memory for the arm chosen early during the trial, perhaps because rats held memories of entrance into the arm within a short-term working memory and that information was lost from working memory through a process of interference. In the present experiment, therefore, the question arose as to whether the functional abnormalities may serve as an indicator of low-level irradiation damage. But the possibility remains that rats exposed to lower doses could have demonstrated a difference in performance on relatively more complex problems rather than easy problem solving abilities. Less