Effect of stress - Induced Malondialdehyde level in different brain tissues in selective subcortical lesioned wistar rats

Brain is the target for different stressors because of its high sensitivity to stress induced degenerative conditions. A number of pathological conditions of the brain have been implicated due to free radical formation. Subcortcial structures are known to influence stress responses. Among them, the amygdala nucleus and the paraventricular nucleus (PVN) of the hypothalamus has been linked in the regulation of stress responses. The present study was aimed to elucidate the comparative analysis of amygdala and paraventricular nucleus in regulating the acute and chronic stress-induced malondialdehyde level in different brain tissues. Wistar albino rats were divided into amygdala lesioned and PVN lesioned groups. Each group was further subdivided into lesioned control group and lesioned stress group. The lesioned stress group animals were subjected to acute and chronic types of swimming and immobilization stress with bilateral lesions of nucleus of amygdala and PVN. Each subgroup contained ten animals. MDA levels of cerebral cortex , hypothalamus and cerebellum were estimated. Exposure to acute and chronic swimming stress in amygdala lesioned groups showed a significant (p < 0.05; p < 0.001) increase in the hypothalamus lipid peroxidation level when compared to the PVN lesioned swimming stress groups. Exposure to acute stressors significantly increased (p < 0.001) the cerebellar lipid peroxidation level in the amygdala lesioned groups when compared to the PVN lesioned groups. Based on the present study, it appears that the amygdala nucleus has a prominent role in decreasing the stress induced free radical formation in brain tissues. It is our attempt to put forth the evidence for greater involvement of the amygdala in the prevention of stress- induced free radicals formation