In the present review we provide extensive overview of the role of reactive oxygen species (ROS)-induced oxidative stress and its fatal effects on brain after TBI.
Arsenic is a key environmental toxicant having significant impacts on human health. Millions of people in developing countries such as Bangladesh, Mexico, Taiwan, and India are affected by arsenic contamination through groundwater. Environmental contamination of arsenic leads to leads to various types of cancers, coronary and neurological ailments in human. There are several sources of arsenic exposure such as drinking water, diet, wood preservatives, smoking, air and cosmetics, while, drinking water is the most explored route. Inorganic arsenic exhibits higher levels of toxicity compared its organic forms. Exposure to inorganic arsenic is known to cause major neurological effects such as cytotoxicity, chromosomal aberration, damage to cellular DNA and genotoxicity. On the other hand, long-term exposure to arsenic may cause neurobehavioral effects in the juvenile stage, which may have detrimental effects in the later stages of life. Thus, it is important to understand the toxicology and underlying molecular mechanism of arsenic which will help to mitigate its detrimental effects. The present review focuses on the epidemiology, and the toxic mechanisms responsible for arsenic induced neurobehavioral diseases, including strategies for its management from water, community and household premises. The review also provides a critical analysis of epigenetic and transgenerational modifications, mitochondrial oxidative stress, molecular mechanisms of arsenic-induced oxidative stress, and neuronal dysfunction.
Stress represents a major risk factor for psychiatric disorders, including post-traumatic stress disorder (PTSD). Recently, we dissected the destabilizing effects of acute stress on the excitatory glutamate system in the prefrontal cortex (PFC). Here, we assessed the effects of single subanesthetic administration of ketamine (10 mg/kg) on glutamate transmission and dendritic arborization in the PFC of footshock (FS)-stressed rats, along with changes in depressive, anxious, and fear extinction behaviors. We found that ketamine, while inducing a mild increase of glutamate release in the PFC of naïve rats, blocked the acute stress-induced enhancement of glutamate release when administered 24 or 72 h before or 6 h after FS. Accordingly, the treatment with ketamine 6 h after FS also reduced the stress-dependent increase of spontaneous excitatory postsynaptic current (sEPSC) amplitude in prelimbic (PL)-PFC. At the same time, ketamine injection 6 h after FS was found to rescue apical dendritic retraction of pyramidal neurons induced by acute stress in PL-PFC and facilitated contextual fear extinction. These results show rapid effects of ketamine in animals subjected to acute FS, in line with previous studies suggesting a therapeutic action of the drug in PTSD models. Our data are consistent with a mechanism of ketamine involving re-establishment of synaptic homeostasis, through restoration of glutamate release, and structural remodeling of dendrites.
Chronic type 2 diabetes (T2D) causes cognitive deficits which are debilitating to the young as well as the older population. Glycogen synthase kinase-3β (GSK-3β) signaling has been reported to be impaired in insulin-resistant and T2D animal models. In this study, we have investigated the involvement of GSK-3β in cognitive deficits associated with T2D using SB216763, a GSK-3 β inhibitor. In high-fat diet-streptozotocin (HFD-STZ) model of T2D in rats, cognitive deficits appeared on the 15th week after induction of diabetes. Treatment with GSK-3β inhibitor SB216763 (i.p. daily for 3 weeks) reversed impaired cognitive performance in the Morris water maze, Y-maze, and passive avoidance tests. Administration of SB216763 also significantly improved acetylcholine esterase activity, GABA, and glutamate levels in the hippocampus and cortex of diabetic rats. Importantly, GSK-3β inhibition showed an increase in pGSK-3β and pCREB expression and reduction in pNF-κB-p65 expression in both hippocampus and cortex. Neuroinflammation was reduced by SB216763 in diabetic rats as evident from reduction in IL-6, TNF-α, COX-2, and inducible nitric oxide synthase levels. This study suggests that cognitive deficits associated with diabetes involved intricate compartmental interaction between transcription factors and neurotransmitter homeostasis/energy metabolism, and GSK-β might play a central role in diabetes-induced cognitive impairment.
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