Unilateral degeneration in hippocampus of female rat

A number of investigations have shown that hippocampal sub regions are particularly vulnerable during stressful conditions [1-5]. Cell loss in hippocampus during normal ageing and also in age-related disorders has also been reported [6]. During the exposure to acute or chronic stress and ischemia, cell loss in hippocampus has been demonstrated [7,8]. Exposure to external stressors like heat can damage hippocampus [9,10]. It has been exhibited that glucocorticoids, which are secreted during the stress, play an important role in stress-related pathological consequences [11]. Excess of glucocorticoids or prolonged exposure to them may enhance neurotoxic insults in brain [12,13] and increase age-related loss of pyramidal cells in hippocampi of rats [14]. Degeneration is depicted by enlarged intracellular spaces, condensation of chromatin, pyknotic neurons in CA1, CA4 and Dg [15]. Cerebral ischemia as a model for analysis of mechanism of neuronal cell death or damage in ischemia is studied by Matsuka et al [16]. CA1 sub region of hippocampus is relatively vulnerable to various stress conditions such as hypoxia and ischemia [1,17]. Cerebral ischemia induces various degrees of brain damage depending on intensity and duration. CA1 pyramidal cells in Mongolian gerbil are selectively damaged even after 3-5 minutes exposure to ischemia [1,18]. In the present study, we report specific neurodegeneration observed in hippocampal sub regions of young adult rats after exposure to swimming stress for a specific period.