Stress In Prefrontal Cortex Research Articles

Selanylimidazopyridine abolishes inflammation- and stress-induced depressive-like behaviors by modulating the oxido-nitrosative system

The 3-[(4-methoxyphenyl)selanyl]-2-phenylimidazo[1,2-a] pyridine (MPI), a novel organic selenium compound, has been receiving increased attention due to its antioxidant effects and its ability to protect against depression-like behaviours. However, it remains elusive whether MPI is able to reverse depressive-like symptoms and biochemical alterations in mice. In the present work, we explored the ability of MPI (10 mg/kg, i.g.) to reverse inflammation- and stress-induced depression-like behaviours in mice injected with tumour necrosis factor (TNF-α) or submitted to acute restraint stress. Depression-like behaviours were evaluated by the tail suspension and splash test and the open field test was used to evaluate the locomotor activity of mice. The prefrontal cortex and hippocampus of mice were used for the evaluation of parameters of oxidonitrosative stress. Here, we showed that a single administration of MPI abolished the depressive-like behaviours induced by TNF-α and acute restraint stress. The oxidative and nitrosative stress presented in mice with depression-like behaviours were also decreased by MPI in the prefrontal cortex and hippocampus. Our findings suggest that MPI presents antidepressant-like activity which is associated with the biochemical regulation of oxidative stress in prefrontal cortex and hippocampus of mice, arising as a promising strategy for the management of depressive symptoms.

Investigation of acupuncture in improving sleep, cognitive and emotion based on attenuation of oxidative stress in prefrontal cortex in sleep-deprived rats

Investigation of acupuncture in improving sleep, cognitive and emotion based on attenuation of oxidative stress in prefrontal cortex in sleep-deprived rats

O49. Ketamine Promotes Fear Extinction and Rescues Dysfunction of Glutamate Release in a Rat Model of PTSD

Stress represents a major risk factor for psychiatric disorders, including Post Traumatic Stress Disorder (PTSD). Recently we dissected the destabilizing effects of acute stress in prefrontal cortex (PFC), with particular relevance to the glutamate system.

Evaluation of antioxidant enzymes in response to predator odor stress in prefrontal cortex and amygdala

Conditions of stress can originate from diverse stimuli including physical, chemical, antigenic and psychological. The latter is processed in part via the hypothalamic-pituitary-adrenal (HPA) axis, with input from and communication between the amygdala (AM) and prefrontal cortex (PFC). The HPA axis generates an increase in circulating glucocorticoids, augmenting metabolism and, consequently, oxygen consumption, increasing the production of free radicals and reactive oxygen species (ROS). Exposure to predator odor as a model of non-invasive acute stress was used to evaluate the hypothesis that psychogenic stress can modify enzymatic antioxidant responses. The activities of various enzymes, catalase (CAT), cytosolic and mitochondrial superoxide dismutase (Cu, Zn-SOD and Mn-SOD, respectively) and glutathione S-transferase (GST), were determined in AM and PFC. Acute psychogenic stress inhibited CAT activity in the AM and PFC, and increased Mn-SOD activity in the PFC. These results demonstrate that different responses can be elicited by the same stressor in two separate brain regions involved in processing emotional stimuli, and that changes in specific antioxidant enzymatic responses can be seen with exposure to acute psychogenic stress.

Increased oxidative stress in prefrontal cortex and hippocampus is related to depressive-like behavior in streptozotocin-diabetic rats

Depression is a common comorbid in diabetic patients. The pathophysiologic mechanisms that relate this comorbidity is not completely elucidated yet, although several lines of evidence point out that increased oxidative stress resulting from hyperglycemia may have a crucial role. Thus, the effect of prolonged treatment with insulin (INS), the antioxidant vitamin E (VIT E) or the antidepressant imipramine (IMI) was evaluated in animals submitted to forced swimming test. Oxidative stress parameters (lipid peroxidation product levels, reduced gluthatione levels and catalase and superoxide dismutase activities) were also evaluated in brain areas related to depression, prefrontal cortex (PFC) and hippocampus (HIP). Our data show that treatment of streptozotocin-induced diabetic (DBT) rats with INS (6UI/day, s.c.) prevented the blood glucose increase, reduced the immobility time, an antidepressant-like behavior, and normalized the reduced weight gain. Although the VIT E treatment (300mg/kg, p.o.) had not altered the blood glucose levels, this treatment was able to reduce the immobility time and to reestablish the reduced weight gain in DBT rats. Differently, treatment with IMI (15mg/kg, i.p.) induced antidepressant-like behavior in normoglycemic besides DBT animals. While VIT E and IMI treatments restored only specific oxidative stress parameters, INS was able to prevent all changed parameters evaluated in both PFC and HIP from DBT animals. Therefore, our data provide further evidence of the importance of oxidative stress in PFC and HIP in the pathophysiology of depression related to diabetes.

Specific subcellular changes in oxidative stress in prefrontal cortex from patients with bipolar disorder

Previously, we found decreased mitochondrial complex I subunits levels and increased protein oxidation and nitration in postmortem prefrontal cortex (PFC) from patients with bipolar disorder (BD) and schizophrenia (SCZ). The objectives of this study were to replicate our findings in an independent sample of subjects with BD, and to examine more specifically oxidative and nitrosative damage to mitochondrial and synaptosomal proteins and lipid peroxidation in myelin. We isolated mitochondria, synaptosomes, and myelin using a percoll gradient from postmortem PFC from patients with BD, SCZ, and healthy controls. Levels of mitochondrial complex I and III proteins, protein oxidation (carbonylation), and nitration (3-nitrotyrosine) were assessed using immunobloting analysis. Lipid peroxidation [lipid hydroperoxides (LPH), 8-isoprostane (8-Iso), 4-hydroxy-2-nonenal (4-HNE)] were measured using colorimetric or ELISA assays. We found decreased complex I subunits levels in BD subjects compared with control (CTL), but no difference in complex III subunits. Carbonylation was increased in synaptosomes from BD group while 3-nitrotyrosine was increased in mitochondria from BD and SCZ groups. 8-Iso was found increased in the BD group while 4-HNE was increased in both SCZ and BD when compared with controls with no differences in LPH. Our results suggest that in BD mitochondrial proteins are more susceptible to potentially reversible nitrosative damage while more longstanding oxidative damage occurs to synaptic proteins. Oxidative stress has been shown to be higher in the brain of patients with bipolar disorder (BD). Here, we demonstrated increased levels of protein oxidation in synaptosomes from postmortem prefrontal cortex from patients from BD group, while 3-nitrotyrosine was increased in mitochondria from BD and schizophrenia (SCZ) groups. Moreover, lipid peroxidation was found increased in the BD when compared with controls; suggesting that in BD mitochondrial proteins are more susceptible to potentially reversible nitrosative damage while more longstanding oxidative damage occurs to synaptic proteins.

Cocaine-induced status epilepticus and death generate oxidative stress in prefrontal cortex and striatum of mice

Oxidative stress (OS) has been related to cocaine's actions and also to numerous nervous system pathologies, including seizures. The purpose of this work was to determine the alterations in glutathione (GSH) content, nitrite/nitrate and MDA levels after cocaine-induced toxicity. Male Swiss mice were injected (i.p.) with cocaine 90 mg/kg and observed during 1 h. After this cocaine overdose some animals presented status epilepticus (SE) while some died after seizures. These animals were divided in two groups, SE and death. A group with an association of the antioxidant Vitamin E (Vit E, 400 mg/kg, i.p.) plus Coc 90 (Vit E plus Coc 90) was undertaken to assess the neuroprotective effect of Vit E. Neurochemical analyses were carried out in prefrontal cortex (PFC) and striatum (ST). GSH levels increased only after cocaine-induced death in both areas studied. Cocaine-induced SE has increased nitrite/nitrate content in PFC and ST, while after death the increase was only in PFC. MDA (the lipid peroxidation marker) was elevated after SE and death in ST and only after death in PFC. Antioxidant treatment significantly reduced the GSH, nitrite/nitrate in ST and MDA levels. Only nitrite/nitrate content in PFC has not been decreased by Vit E pretreatment. The results relate that oxidative stress occurs after cocaine-induced toxicity mainly after death indicating that probably the increase of OS in the animal's brain leads to seizures and death, also showing a protective effect of Vit E in this process. Together with previous results this study contributes to the knowledge of cocaine-induced toxicity and possible in the near future to the use of antioxidants in the prevention of cocaine-induced CNS toxicity.

5-Hydroxytryptophan rescues serotonin response to stress in prefrontal cortex of hyperphenylalaninaemic mice

Adult early treated hyperphenylalaninaemic patients can show specific deficits of prefrontal cortical functions. The development of additional therapeutic strategies for these patients requires the understanding of the mechanisms involved in phenylalanine-dependent impairment of fronto-cortical functions. We tested the hypothesis of phenylalanine interference with aminergic neurotransmission in the prefrontal cortex by evaluating, in vivo, amine release in adult Pah(enu2) mice, the genetic model of phenylketonuria. Mice of healthy background responded to a psychogenic stressor with the classic time-dependent increase of norepinephrine, dopamine and serotonin release from prefrontal cortical terminals. Neither the dopaminergic nor the serotoninergic responses were observable in the Pah(enu2) mice. Temporary reduction of circulating phenylalanine, by phenylalanine-free diet without amino- acid supplement, promoted recovery of the serotonin response only, demonstrating direct interference with serotonin synthesis in the mature brain. Evaluation of different steps of serotonin synthesis in the prefrontal cortex of hyperphenylalaninaemic mice demonstrated inhibition of cortical tryptophan hydroxylase activity. Finally, systemic administration of 5-hydroxytryptophan, the product of tryptophan hydroxylase activity, allowed frontal cortical serotonin response to stress in hyperphenylalaninaemic mice. Collectively, these results demonstrate that hyperphenylalaninaemia interferes with the ability of the mature prefrontal cortex to respond to psychological challenges, point to serotonin synthesis as the target of phenylalanine interference, and support the use of 5-hydroxytryptophan in lifelong treatment of hyperphenylalaninaemic subjects.

Effect of acute and chronic exercise on oxidant–antioxidant equilibrium in rat hippocampus, prefrontal cortex and striatum

Although regular physical exercise is beneficial to the body, it is well known that exhaustive exercise causes oxidative stress in muscle. Recent studies suggest that regular moderate physical exercise has the beneficial effects on brain. There is a little information regarding whether or not exercise could generate oxidative stress in the brain and the findings are conflicting. The aim of this study was to investigate the effects of acute and chronic exercise on thiobarbituric acid reactive substances, as an indicator of lipid peroxidation, in the hippocampus, which has a high concentration of glucocorticoid receptors, and prefrontal cortex and striatum, which have high dopamine content. Additionally we examined antioxidant enzyme activities, superoxide dismutase and glutathione peroxidase and nitrite–nitrate levels to assess the effects of reactive oxygen and nitrogen species. In this study it was shown that acute treadmill exercise at different strengths did not cause oxidative stress in prefrontal cortex, striatum and hypocampus regions of the brain. Regular treadmill exercise performed at different strengths was shown not to cause oxidative stress in prefrontal cortex, striatum and hippocampus regions of brain. As a result, we propose that acute and chronic exercise do not cause oxidant stress in prefrontal cortex, striatum and hippocampus and chronic exercise has a favorable effect on hippocampus, possibly by decreasing superoxide radical formation.

Oxidative stress in prefrontal cortex of rat exposed to MK-801 and protective effects of CAPE

MK-801 was shown to be one of the most neurotoxic non-competitive NMDA receptor antagonists. It is known that repeated injection of MK-801 was proposed in an animal model in psychosis. The aims of this study are to investigate the contributing effect of oxidative stress in MK-801-induced experimental psychosis model, and to show that prevention of oxidative stress may improve prognosis. Furthermore, there is evidence that oxygen free radicals play an important role in the pathophysiology of schizophrenia. In this study, Wistar Albino rats were divided into three groups: 1st group: Control, 2nd group: MK-801, 3rd group: MK-801 + CAPE (Caffeic acid phenethyl ester) group. MK-801 was given intraperitoneally at the dose of 0.5 mg/kg/day for 5 days. CAPE was given to the treatment group while exposed to MK-801. In control group, saline was given intraperitoneally at the same time. After 7 days, rats were killed by decapitation. Prefrontal cortex (PFC) of rats was removed for biochemical and histological analyses. As a result, malondialdehyde (MDA), protein carbonyl (PC), nitric oxide (NO) levels and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and xanthine oxidase (XO) and adenosine deaminase (AD) enzyme activities were found to be increased significantly in prefrontal cortex (PFC) of MK-801 group ( p < 0.0001) compared to control group. In CAPE treated rats, prefrontal tissue MDA, PC, NO levels and, GSH-Px, XO, AD enzyme activities were significantly decreased when compared to MK-801 groups ( p < 0.0001) whereas catalase (CAT) enzyme activity was not changed. Moreover, in the light of microscopic examination of MK-801 groups, a great number of apoptotic cells were observed. CAPE treatment decreased the apoptotic cell count in PFC. The results of this study showed that MK-801-induced neurotoxicity caused oxidative stress in PFC of rats. This experimental study may also provide some evidences for the new treatment strategies with antioxidants in schizophrenia.