Physiology of stress and the involvement of reactive oxidative species: A mini-review

ABSTRACT Stress is evident amongst all organisms as a part of their life. It triggers various neurohormonal changes to restore homeostasis. Physiological responses and psychological changes occur during stress. The hypothalamic pituitary adrenal (HPA) axis and sympathetic nervous system (SNS) play a major role in response to stress. SNS acts via norepinephrine through subcortical activation of the locus coeruleus. Reactive oxygen species (ROS) are the derivatives of oxygen, which produce free radicals. The cell membrane contains a high level of unsaturated fatty acids that is damaged by ROS oxidation. Protein damages occur directly or indirectly by ROS by fragmentation, peroxidation, structural changes, proteolysis and formation of cross-linkages. ROS can damage DNA bases and deoxyribose sugars; cause purine losses, DNA strand breaks, DNA-protein cross-linkages and harm to the DNA repair mechanism. Higher levels of ROS lead to disease states. Understanding the mechanisms and significance of ROS involving pathways may help to reveal therapeutic strategies for diseases