The Effects of Chronic Hyperoxia (80%) on the Behavior of Rat Litters

Abstract

In our previous reports it was shown that oxygen at 40% and 80% inhibited pregnancy and birth rate of rats (4, 5). In this study, pregnant female rats in the third trimester were exposed to hyperoxia and the births were performed in a hyperoxic cabin. The action of hyperoxia is known to be stressful for living organisms. Brain and lungs are two organs which are most sensitive to hyperoxia, and have been intensively investigated (3, 7, 8, 11). Extensive literature exists regarding the acute effects and toxicity of normobaric hyperoxia (3, 12). Few reports have appeared to examine behavioral changes in rats that were exposed chronically to hyperoxia (8–10). On the other hand, the cerebral circulation is sensitive to changes in blood oxygen. Also, hyperoxia reduced cerebral blood flow (3). Low blood flow will especially influence the brain stem, a region that is vulnerable, and develop specific necrosis during hyperoxic oxygen exposure (1). There is also evidence that the central nervous system (CNS) is particularly sensitive to the toxic effects of hyperoxia, even three hours exposure with 95% oxygen produced neural necrosis in the rat (2). The study has been carried out to obtain chronic hyperoxic rat litters and to investigate the effects of hyperoxic conditions on the changes of behavioral patterns of the rat litters (6). This is the reason, we chose these parameters to get a suitable method for testing ontogeny of open field behavior to determine hyperoxic-caused modifications of locomotor activity.