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Post-traumatic stress disorder (PTSD) is a psychological disorder affecting many around the world. Growing evidence suggests that orexin-A is involved in the pathophysiology of depression and panic anxiety disorder. However, the role of orexin-A in PTSD remains unclear. Therefore, pharmacological manipulation of orexin-A can be a potential approach for the treatment of PTSD. Male Wistar rats were subjected to stress re-stress (SRS) by restraining them for 2 h followed by foot shock (FS) and halothane exposure on day-2 (D-2). Then the rats were weekly exposed to FS as re-stress cue . Suvorexant, an orexin antagonist (10, 20 and 30 mg/kg p.o.) and paroxetine (10 mg/kg p.o.) were administered from D-8 to D-32. Plasma and cerebrospinal fluid (CSF) were collected for corticosterone and orexin-A measurement. The analysis of serotonin and corticotropin-releasing factor receptor-1 (CRF-R1) were performed in the amygdalar tissue. SRS-induced PTSD-like symptoms like fear response, anxiety-like behaviour and hypocorticosteronism were attenuated by suvorexant and paroxetine. Interestingly, SRS exposed rats showed activation of orexin-A and serotonergic systems, which were also attenuated by suvorexant. Additionally, suvorexant ameliorated the extrahypothalamic induced upregulation of CRH-R1 in SRS-exposed rats. Therefore, orexin-A may be considered as a neurochemical-marker for PTSD and suvorexant alleviated PTSD-like symptoms through modulating orexinergic, serotonergic and neuroendocrine systems., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Caffeine is the widely consumed central nervous system stimulant in form of coffee and other beverages. However, the repeated administration of caffeine induces anxiety, disturbance in hypothalamic-pituitary-adrenal (HPA) axis and psychiatric symptoms in humans. As much evidence links PTSD to HPA axis dysfunction, and anxiety is a hallmark symptom, repeated and/or large doses of caffeine may exacerbate symptoms of PTSD., Objective: In our present study, we evaluated the effect of repeated administration of caffeine on stress re-stress (SRS) model of PTSD., Methods: As per the protocol, male rats were restrained for 2 h followed by 20 min forced swim and halothane anaesthesia on day 2 (D-2). Then the rats were re-stressed (forced swim) at 6-days interval between D-8 to D-32. After exposure to SRS, depressive, anxiety-like behaviour, and cognitive functions were evaluated by forced swim test (FST), elevated plus maze (EPM) and Y-maze tests respectively. Caffeine (10, 20 and 30 mg/kg, i.p.) dosing was started from D-8 and continued up to D-32. The corticosterone level was measured in plasma followed by serotonin and glucocorticoid receptor (GR) and mineralocorticoid receptors (MR) estimation in hippocampus (HIP), prefrontal cortex (PFC) and amygdala (AMY)., Results: SRS-induced depressive and anxiety-like behaviour was aggravated by caffeine at dose of 20 and 30 mg/kg. Caffeine (30 mg/kg) treated control animals showed depressive, anxiety-like behaviour and cognitive impairments. SRS-induced decrease in plasma corticosterone level and increase in serotonin (5HT) levels in the PFC, HIP and AMY were not altered by caffeine. Caffeine did not modulate the SRS-induced decrease in glucocorticoid receptor (GR) and mineralocorticoid receptor (MR). In contrast, caffeine per se decreased GR and MR expression and their ratio in unstressed animals., Conclusion: Repeated intake of caffeine aggravates PTSD-like symptoms in stress-exposed rats and induces PTSD-like symptoms in unstressed rats by altering the expression of glucocorticoid receptors., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Post-traumatic stress disorder (PTSD) develops after exposure to a severe traumatic event. Stress re-stress (SRS) model of PTSD using forced swim as a re-stress shows hypocortisolism, an index of hypothalamic–pituitary–adrenal (HPA) axis dysfunction. Despite this, the SRS model lacks development of hyperarousal and intrusive memory which are prominent symptoms of PTSD. Aim: Developing a model which shows more clinical similarities to PTSD. We used intense foot-shock (FS) (2 mA for 10 sec) instead of the forced-swim test (FST) as a re-stress cue. Methods: The stress session was performed on D-2 except control group. The FST group rats were forced to swim for 20 min, and FS group rats were exposed to foot shock of 2 mA for 10 sec. The re-stress sessions of FST and FS were performed on D-8, 14, 20, 26 and 32. The freezing behavior was evaluated after the FS re-stress cue, and remaining behavioral assessments such as anxiety and depressive-like behavior, and cognitive dysfunction were performed on last day of the experiment. Results: The FS-induced PTSD-like (anxiety and depressive-like behavior, and cognitive dysfunction) symptoms and a decrease in plasma corticosterone were more significant compared to FST. The hyperarousal and intrusive memory induced by FS were additional symptoms in the SRS model. Treatment with paroxetine significantly attenuated FST and FS-induced behavioral deficits in PTSD rats. Conclusion: FS as a re-stress model shows prominent PTSD-like symptoms with HPA axis dysfunction compared to FST. [ABSTRACT FROM AUTHOR]

Binge eating disorder (BED) is a stress-related disorder characterized by acute episodes of excessive food intake. Piracetam, a nootropic agent has been reported to show several other neuropharmacological properties. The present study, evaluated the pharmacological effect of piracetam (200 mg/kg i.p.) on BED in female rats, induced by free access to palatable cookies for 2 h on alternate days. BED was confirmed by an increase in binge eating behavior and weight gain. BED leads to anxiety, cognitive and memory deficits, as evaluated by EPM (Elevated plus maze), OFT (open field test), and Y-maze tests. Increased levels of plasma corticosterone (CORT), glutamate in nucleus accumbens (NAC), hypothalamus (HYP) and prefrontal cortex (PFC) indicate stress and excitotoxicity. Moreover, it was observed that the levels of dopamine were higher in NAC and PFC, and less in HYP which may be responsible for motivational behavior for palatable feeding and cognitive deficits. More surprisingly, feeding behaviour regulating hormones namelyleptin was increased and ghrelin level was decreased in BED. Further, level of acetylcholine which regulates cognitive behaviour was compromised in BED. Piracetam significantly decreased binge eating behavior and associated body weight and regulated the levels of concerned neurotransmitters in respective regions. However, piracetam did not alter normal feeding behavior in the fast-refed model. Further, piracetam showed brain region-specific decrease in vascular endothelial growth factor expression. Piracetam showed anxiolytic activity and also alleviated cognitive deficit observed in BED. Hence, preclinical evidence indicates the potential use of piracetam for the treatment of BED. [ABSTRACT FROM AUTHOR]

Context: Eugenol, an essential constituent found in plants such as Eugenia caryophyllata Thunb. (Myrtaceae) is reported to possess neuroprotective and anti-stress activities. These activities can potentially be useful in the treatment of stress-induced irritable bowel syndrome (IBS). Objective: The protective effect of eugenol was assessed against restraint stress (RS)-induced IBS-like gastrointestinal dysfunction in rats. Further, its centrally mediated effect was evaluated in this model. Materials and methods: Eugenol (12.5, 25, and 50 mg/kg), ondansetron (4.0 mg/kg, p.o.), and vehicle were administered to rats for 7 consecutive days before exposure to 1 h RS. One control group was not exposed to RS-induction. The effect of eugenol (50 mg/kg) with and without RS exposure was evaluated for mechanism of action and per se effect, respectively. The hypothalamic-pituitary-adrenal cortex (HPA)-axis function was evaluated by estimating the plasma corticosterone level. The levels of brain monoamines, namely serotonin, norepinephrine, dopamine, and their metabolites were estimated in stress-responsive regions such as hippocampus, hypothalamus, pre-frontal cortex (PFC), and amygdala. Oxidative damage and antioxidant defenses were also assessed in brain regions. Results: Eugenol (50 mg/kg) reduced 80% of RS-induced increase in fecal pellets similar to that of ondansetron. Eugenol attenuated 80% of stress-induced increase in plasma corticosterone and modulated the serotonergic system in the PFC and amygdala. Eugenol attenuated stress-induced changes in norepinephrine and potentiated the antioxidant defense system in all brain regions. Conclusion: Eugenol protected against RS-induced development of IBS-like gastrointestinal dysfunction through modulation of HPA-axis and brain monoaminergic pathways apart from its antioxidant effect. [ABSTRACT FROM AUTHOR]

Abstract: The management for post-traumatic stress disorder (PTSD) involves chronic administration of drugs. We have modified the stress re-stress (SRS) model to study the effect of chronic administration of risperidone (RIS) after induction of PTSD in rats. On day-1 (D-1) rats underwent training session for elevated-plus maze (EPM) test. On D-2, rats were subjected to stress protocol of 2 h restraint and 20 min forced-swim test (FST) followed by halothane anesthesia. The rats were exposed to re-stress (FST) on D-8 and at six day intervals on D-14, D-20, D-26 and D-32. The rats were treated with RIS (0.01, 0.1 and 1.0 mg/kg; p.o.) and standard drug, paroxetine (PAX; 10.0 mg/kg; p.o.) from D-8 to D-32. RIS (0.1 mg/kg) and PAX ameliorated SRS-induced immobility. RIS in median dose reversed SRS-induced hypocorticosteronemia both in urine and plasma. RIS in median dose improved SRS-induced behavioral perturbations such as memory impairment and anxiety-like behavior in EPM and Y-maze tests. RIS (0.1 mg/kg) reversed SRS-induced increase in amygdalar serotonin level. RIS (0.1 mg/kg) increased the expression of hippocampal MR thereby reversing the SRS-induced decrease in MR/GR ratio. Pearson's analysis of data on D-32 showed that there was significant correlation of plasma corticosterone, amygdalar serotonin and hippocampal ratio of mineralocorticoid (MR)/glucocorticoid receptor (GR) with SRS-induced behavioral abnormalities. Hence, median dose of RIS shows anti-PTSD-like effect in the modified SRS model. PAX had earlier onset of action in ameliorating behavioral effects of PTSD compared to RIS. However, RIS showed anti-PTSD like effect in sub-therapeutic dose. The mode of anti-PTSD action of RIS seems to involve the HPA-axis and serotonergic system, whereas PAX did not show any significant action on these pathways. The effect of repeated treatment of drugs for PTSD can be evaluated using the modified SRS model. [Copyright &y& Elsevier]

Objectives Asparagus racemosus (AR) is classified as an adaptogen, an important medicinal plant and food. Even though AR is widely used as food and nutraceutical, it has only been evaluated in the context of experimental disorders. Hence, the present study was designed to evaluate the effect of standardized methanolic extract of AR (MAR) on experimentally un-manipulated animals to observe the per se effects on stress pathways. Methods MAR (50, 100, and 200 mg/kg, per oral) was administered for 7 days. Lorazepam (0.5 mg/kg, intraperitoneal) was used as a positive control. On the seventh day, plasma was collected for the estimation of corticosterone (CORT) and norepinephrine (NE), and brain was microdissected into hippocampus, hypothalamus (HYP), pre-frontal cortex, amygdala, and nucleus accumbens to estimate tissue level of monoamines (serotonin, dopamine, and NE), their metabolites, and turnover. Results MAR dose-dependently decreased the plasma CORT and NE levels, indicating its effects on the hypothalamic-pituitary-adrenal cortex axis and the sympathetic-noradrenergic system, respectively. MAR increased the levels of all monoamines in the HYP. However, MAR showed region-specific changes in monoamines and their metabolites, and turnover in other brain regions. Discussion MAR showed a physiological modulation of the stress pathways. Interestingly, in most brain regions the change in monoaminergic systems was limited by a ceiling effect at a dose of 100 mg/kg. These observations could explain the traditional use of AR as an adaptogen and a functional food. [ABSTRACT FROM AUTHOR]

The present investigation evaluates the anti-stress activity of risperidone (RIS) in the cold restraint stress (CRS) model and related stress pathways. Rats were pretreated with RIS (0.1 and 1.0 mg/kg) for 21 days before subjecting to CRS. Ultra low dose of RIS (ULD; 0.1 mg/kg) in contrast to higher dose (1.0 mg/kg) significantly reduced stress in terms of ulcer index. ULD also reversed stress-induced increase in plasma corticosterone and norepinephrine levels used as markers for the function of hypothalamo-pituitary-adrenal (HPA) axis and sympathetic nervous system (SNS) respectively. ULD caused dose and brain region (hippocampus, prefrontal cortex and striatum) specific changes to stress-induced perturbations of serotonin, dopamine and its metabolites indicating modulation of brain monoaminergic system (BMS). ULD did not show any extrapyramidal side effects. Thus, the anti-stress effect ULD is probably mediated through the HPA axis, SNS and BMS. The study indicates a potential use of ULD in stress disorders. [ABSTRACT FROM AUTHOR]

Stress is the leading psychopathological cause for several mental disorders. Physiological and psychological responses to stress are mediated by the hypothalamic--pituitary--adrenal (HPA), sympathoadrenal system (SAS), and brain monoaminergic systems (BMS). Eugenol is reported to substantially modulate brain functions by regulating voltage-gated cation channels and release of neurotransmitters. This study was designed to evaluate the anti-stress effect of eugenol in the 4-h restraint model using rats. Ulcer index was measured as a parameter of the stress response. HPA axis and the SAS were monitored by estimating plasma corticosterone and norepinephrine (NE), respectively. Analysis of NE, serotonin (5-HT), dopamine, and their metabolites in discrete brain regions was performed to understand the role of BMS in the anti-stress effect of eugenol. Stress exposure increased the ulcer index as well as plasma corticosterone and NE levels. Eugenol pretreatment for 7 days decreased the stress-induced increase in ulcer index and plasma corticosterone but not NE levels, indicating a preferential effect on the HPA axis. Furthermore, eugenol showed a ''U''-shaped dose--response curve in decreasing ulcer index and plasma corticosterone levels. Eugenol also reversed the stress-induced changes in 5-HT levels in all brain regions, whereas NE levels were reversed in all brain regions except hippocampus. These results suggest that eugenol possesses significant anti-stress activity in the 4-h restraint model and the effect is due to modulation of HPA and BMS. [ABSTRACT FROM AUTHOR]