فهرست مطالب maryam radahmadi

The efficacy of escitalopram, a pharmaceutical antidepressant, and exercise, a lifestyle intervention, in mitigating depressive symptoms has been established. This study investigated the impact of varying doses of escitalopram and the combination of forced exercise with escitalopram on stress-induced depressive-like behavior in male rats.

 Sixty-four male rats were allocated into eight groups: control (Co), sham (Sh), depression without treatment (Dep-WT), depression with exercise (Dep-Exe), depression with escitalopram at 10 mg/kg (Dep-Esc10), depression with escitalopram at 20 mg/kg (Dep-Esc20), depression with escitalopram at 10 mg/kg combined with exercise (Dep-Esc10-Exe), and depression with escitalopram at 20 mg/kg combined with exercise (Dep-Esc20-Exe). To induce depression, chronic restraint stress was administered for 6 hours per day over a period of 14 days.Following the stress induction period, rats were administered escitalopram (at doses of 10 or 20 mg/kg, i.p), subjected to treadmill running (20-21 m/min for 1 h/day), or subjected to a combination of both interventions. Depressive-like behaviour induced by stress and locomotor activity were assessed using the forced swimming test (FST) and the open field test (OFT), respectively.

 In the FST, the immobility time significantly increased in the Dep-WT, Dep-Exe, and Dep-Esc10 groups, while it significantly decreased in the Dep-Esc20, Dep-Esc10-Exe, and Dep-Esc20-Exe groups compared to the Dep-WT group. In the OFT, the central time and total travelled distance significantly decreased in the Dep-WT group. Conversely, central time significantly increased in the Dep-Esc10-Exe and Dep-Esc20-Exe groups, and all treatment groups exhibited a significant increase in central time compared to the Dep-WT group.

The findings suggest that combining exercise with escitalopram yields additive effects, representing a promising treatment protocol for anxiety, depression, and locomotor activity.

Empathy is critical for social interactions. Nevertheless, the sharing of excessive negative emotions may affect the behaviors of the observer and demonstrator in social equality and inequality conditions. The present study investigated the effects of chronic empathic and reversed empathic stress on anxiety-like behaviors and their correlation with serum corticosterone levels in male rats.

Forty-eight male Wistar rats were divided into six groups: Control, Pseudo-Observer, Pseudo-Demonstrator, Observer, Demonstrator, and Co-Demonstrator. Various types of stress included dyadic stress in social inequality conditions, such as empathic and reversed-empathic (restrained) stress, dyadic stress in social equality (receiving common stress), and single stress (restrained and unrestrained) as sham stress groups. All of these stressors were induced for 2h/day for 21 days. The time spent in the open arms and the number of entries in the open arms were measured during the elevated plus maze test to assess anxiety-like behavior. The correlations between serum corticosterone levels and OAT% were evaluated for all experimental groups.

The percent of total time spent in the open arms and the number of open arm entries were significantly decreased in all stressed groups. Moreover, there was a significant negative correlation between serum corticosterone levels and the percent of total time spent in the open arms in all experimental groups, except the control and pseudo-observer groups.

According to the present findings, chronic empathic stress (observing others' psychological stress or distress) could induce anxiety in the observers. In addition, the reversed empathic stress (receiving restraint stress in the presence of a familiar cagemate in social inequality condition) can be unexpectedly effective in the induction of anxiety. It seems that the gradual changes in serum corticosterone levels play an essential role in the development of anxiety-like behaviors.

Psychological stress impairs cognitive performance and affects mood states. This study compares the effect of four types of psychological stress (crowding, relocation, isolation, and restraint) on locomotor activity, learning, and memory, as well as anxiety-like behaviors performed by the open field, elevated plus maze, and passive avoidance tests.

Wistar rats were randomly assigned to different groups of crowding, relocation, isolation, and restraint stress, and control. The stress induction was administered for 21 consecutive days (6 h/day). To evaluate various types of behaviors, the open field, elevated plus maze, and passive avoidance tests were employed.

According to the PA test results, the latency to enter the darkroom decreased significantly in all stress groups, especially in the crowding and isolation stress groups. However, it had an inverse relationship with serum corticosterone (CORT) levels. The total dark stay time increased significantly in the restraint and crowding stress groups, and also particularly, in the isolation stress group. In the isolation stress group, the number of darkroom entries decreased significantly. All stress groups spent a significantly shorter time in the open arms of the EPM apparatus. Finally, the total distance traveled, in the open field test was significantly lower in all stress groups, particularly in the isolation stress group.

Crowding and social isolation were the two stress types that had the most adverse effect on cognitive performance, as they induced stress-driven anxiety-like behaviors, probably due to increased CORT secretion. A high or low population of social density may create a condition, in which the nervous system could not efficiently manage stress, particularly at chronic levels.

Light-dark cycles regulate the body’s physiological activity; hence, marked changes in these cycles could lead to conditions with impaired brain functions and disrupted moods (e.g., stress). Therefore, this study compared the impact of stress due to various photoperiodic durations on anxiety-like behavior, learning, memory, locomotor activity and memory consolidation in rats.

Thirty-five male rats were divided into five groups with different light(L)-dark(D) cycles: L20/D4, L16/D8, L12/D12 (control), L8/D16 and L4/D20 groups. After14 days, the elevated plus-maze (EPM) and passive avoidance (PA) tests were performed to assess the anxiety-like behaviors and brain functions.

The percentage of spent time, number of entries to the open arm of the EPM test and the entrance latency to the dark room of the PA test decreased significantly in the L20/D4 and L4/D20 groups; however, the reduction of latency to enter the dark room was particularly significant in the L20/D4 group. In addition, there were significant differences between the initial latency and latency after one day (as learning) in all experimental groups. The total dark stay time increased significantly in different photoperiods.

An abnormal light-dark length could disrupt certain brain functions, such as learning, memory, locomotor activity, memory consolidation and anxiety-like behavioral responses at different levels in a time-independent manner. The light-dark length (both minimum and especially the maximum day length) led to increased learning impairment and memory deficits, as well as worsened anxiety-like behaviors. The memory consolidation was also disrupted with various photoperiods.

Depression is a prevalent mental disorder that reduces the quality of life. It is associated with various psychological, behavioral, and physiological symptoms. A combination of genetic, epigenetic, and environmental factors could be traced in depression etiology. Depression affects various parts of the brain, becoming hypoactive and/or hyperactive. Various functions are impaired in depression due to the deregulated secretion of brain neurotransmitters, hormones, and growth factors. Moreover, it leads to immune system dysfunction and structural brain alterations. Therefore, administering proper and effective treatment for depression requires comprehensive knowledge of its underlying causes. All in all, the overview of the role of different brain areas and some of their influencing factors could be beneficial for the treatment of depression.

Crocin and stress affect different aspects of brain functions. Chronic isolation stress is prevalent in today’s world. Therefore, this study investigated the impact of crocin and chronic isolation stress on learning, memory, and different brain waves in male rats.

Forty male Wistar rats were allocated to five groups: control, sham, chronic isolation stress (CIS), two stress groups receiving different doses of crocin (CIS-Cr30 and CIS-Cr60). Both chronic isolation stress (6h/day) and crocin administration were induced for 21 days. The passive avoidance test evaluated initial and step-through latencies (IL and STL, respectively), as well as total dark compartment, and stay time. Also, different brain waves were measured by EEG recording.

The STL declined in the CIS and CIS-Cr30 groups while it significantly increased in only the CIS-Cr60 group. Also, the total dark compartment stay time increased in the CIS group, whereas it decreased by crocin (30 and 60 mg/kg) in the CIS group. The percentages of beta and alpha waves decreased whereas theta waves significantly increased in the CIS group. While the percentage of the beta and alpha waves increased as well as the percentage of the theta and delta waves decreased by crocin at a dose of 60 mg/kg in the CIS group.

Cronic isolation stress was so destructive and it impaired learning, memory as well as alpha, beta, and theta waves in the brain. Only a dose of 60 mg/Kg of crocin reversed memory deficit and affected all brain waves in subjects under chronic isolation stress. Therefore, the doses of 60 and 30 mg/kg of crocin had different effects on electrophysiological and behavioral brain functions under chronic isolation conditions.

Administration of antidepressants and exercise are among the therapeutic approaches to chronic stress. Therefore, this study compared the therapeutic effects of different doses of escitalopram, exercise, and exercise-accompanied escitalopram on synaptic potency and long-term plasticity in the hippocampal CA1 area in rats under chronic restraint stress.

The rats were allocated to different groups. The chronic restraint stress (6 hr/day) continued for 14 days. Injection of escitalopram (10 and 20 mg/kg) and treadmill running (1 hr/day) were performed after the stress induction. The input/output (I/O) functions and LTP induction were evaluated in the hippocampal CA1 area.

The fEPSP slope and amplitude after the LTP induction significantly decreased in the chronically stressed group. However, the serum corticosterone levels had significant enhancement in this group. In addition to serum corticosterone levels, the fEPSP slope and amplitude after the LTP induction were enhanced by exercise, escitalopram 20 mg/kg alone, and exercise-accompanied escitalopram 10 and/or 20 mg/kg in chronically stressed groups.

Overall, chronic stress impaired synaptic potency and long-term plasticity. These impairments were effectively reversed by exercise, escitalopram 20 mg/kg alone, and exercise-accompanied escitalopram 10 and 20 mg/kg. However, escitalopram 10 mg/kg alone could not alleviate the memory deficits in chronically stressed subjects. Therefore, exercise with both doses of escitalopram seems to have had additive effects on chronic stress conditions.

People mainly have a major interest in eating some palatable foods such as chocolate and sweet foods that influence brain functions. This study investigated the effects of acute, sub-chronic and chronic chocolate consumption with different percent of cocoa/sugar on learning, memory, memory consolidation and electroencephalogram (EEG) waves in rats.

Thirty-five male Wistar rats were allocated to five main groups containing control and sucrose as well as dark, milk and white chocolate groups. All groups were freely fed with chow, different kinds of chocolate and sucrose separately for 1,7 and 14 days as acute, sub-chronic and chronic food consumption. Also, memory and memory consolidation were evaluated using a passive avoidance test on days 1,7 and 14. In addition, brain electrical activity was evaluated by EEG.

Acute and sub-chronic dark and milk chocolate consumption significantly improved latency after day 1 and particularly day 7. In addition, only the chronic dark chocolate diet showed a significant enhancement in latency after 14 days. White chocolate and sucrose diets did not have significant effects on three latencies. The milk and dark chocolate diets changed nearly all brain waves of EEG, while the sucrose diet did not affect any of them.

Unlike sucrose and white chocolate, dark chocolate (acute, sub-chronic and chronic consumption) and milk chocolates (acute and sub-chronic consumption) had beneficial effects on memory and nearly all electrical brain activity probably due to high levels of cocoa and perhaps its antioxidant effect. Hence, these types of diets modified brain homeostasis and increased conscious state and relaxation reduction.

Depression impairs brain functions and memory processes. In a state of depression, escitalopram (as an antidepressant drug) and exercise (as an alternative lifestyle) both affect brain functions. Therefore, this study compared the therapeutic effects of exercise, using escitalopram at two different doses and exercise-accompanied escitalopram on different aspects of brain functions in rats with depression.

Male rats were randomly allocated into nine different groups of control, sham, depression, depression-rest, depression-exercise, depression-escitalopram 10, depressionescitalopram 20, depression-escitalopram 10-exercise and depression-escitalopram 20-exercise. Chronic restraint stress (6h/day, 14 days) was applied to induce depression. The escitalopram injections and treadmill running (1h/day, 14 days) were performed after the stress-induced depression. Moreover, different aspects of brain functions like learning, memory, memory consolidation and locomotor activity were evaluated via the passive avoidance test.

The results indicated that depression disrupted learning, memory and memory consolidation. Escitalopram at a dose of 20mg/kg, exercise-accompanied escitalopram 20mg/ kg and only exercise improved them significantly. In rats with depression, escitalopram at a dose of 10mg/kg (with and without exercise) enhanced memory in depression non-significantly. Moreover, the locomotor activity was decreased in groups with exercise-accompanied escitalopram 20mg/kg and exercise compared to only allowing a rest period after depression.

Overall, escitalopram 20mg/kg, exercise-accompanied escitalopram 20mg/kg and only exercise had therapeutic effects on memory improvement in subjects with depression. Since the combination of escitalopram 20mg/kg and exercise had a partial additive effect, it was the best treatment protocol for reversing the memory deficits in rats with depression.

The lack of social communication is associated with the primary risk of proper brain functions. It is reported that crocin helps relieve this problem. The present study examined the protective effect of two doses of crocin on Long-term potentiation (LTP) of hippocampal cornu ammonis 1 (CA1) area as a cellular mechanism in rats exposed to chronic social isolated stress.

Rats were assigned to the control, sham, isolation stress, and two stress groups (receiving 30 and 60 mg/kg crocin). Chronic isolation stress (CIS) was induced 6 h/d, and crocin was administrated for 21 days. The field excitatory postsynaptic potential (fEPSP) slope and amplitude were measured by input/output functions and LTP induction in the CA1 area of the hippocampus. Also, the corticosterone and glucose levels were assayed in the hippocampus and frontal cortex.

The slope and amplitude of fEPSP severity were impaired in both input/output and LTP responses in the CIS group. Crocin at a dose of 30 and particularly 60 mg/kg improved input/output and LTP responses in the CIS group. Also, the corticosterone levels significantly increased in the frontal cortex and especially the hippocampus. In contrast, only a high dose of crocin decreased hippocampal corticosterone levels in the CIS condition. Finally, the glucose levels did not change in the hippocampus and frontal cortex in all experimental groups. 

The chronic isolation stress impaired neural excitability and Long-term plasticity in the CA1 area due to elevated corticosterone in the hippocampus and probably the frontal cortex. The low and high doses of crocin improved excitability and Long-term plasticity in the chronic isolation stress group by only decreasing corticosterone levels in the hippocampus, but not the frontal cortex.

Stress influences brain functions adversely but escitalopram exhibits positive effects on cognitive processes. Therefore, this study investigated the protective effects of different escitalopram doses on cognitive functions in rats under chronic stress and normal conditions.

Forty-nine rats were randomly allocated into seven groups: control, sham, stress, escitalopram (10, 20 mg/kg/day) and stress-escitalopram (both doses). Initial latency, latency after 1-day, dark stay (DS) time and the number of entrances to the dark compartment were evaluated by passive avoidance test.

There were significant latency differences in stress and escitalopram10 groups compared to control group. Additionally, latencies showed significant enhancements in both 10 and 20 mg/kg/day stress-escitalopram groups compared to stress group and significant decrease in escitalopram20 group with respect to escitalopram10 group. DS time was significantly higher in stressed group and significantly lower in escitalopram10 groups, both compared to control group. Also, it was significantly lower in both stress-escitalopram groups in comparison with stress group. Furthermore, escitalopram20 group had a significantly higher DS time compared to escitalopram10 group. Finally, the number of entrances to the dark compartment was significantly lower in stress, escitalopram10 and stress-escitalopram10 groups compared to control group.

Different doses of escitalopram affected brain functions under chronic stress and normal conditions. Escitalopram10 presented the most beneficial effects on improving brain functions under normal conditions. Whereas, both escitalopram doses showed similar protective effects on memory under stress. Overall, escitalopram at a dose of 10 mg/kg/day improved learning, memory consolidation and locomotor activity better than its maximum dose of 20 mg/kg/day.

 Different nutrients affect brain functions. This research investigated the effects of acute, sub-chronic, and chronic consumption of sucrose and different kinds of chocolate (with various cocoa and carbohydrate percentage) as portable nutrients on anxiety, locomotor activity, food consumption, and body weight differences (BWD) in male rats.

 Thirty-five male Wistar rats (200-250 g) were divided into five experimental groups: standard food (control), dark chocolate, milk chocolate, white chocolate, and sucrose for 14 days. Anxiety and locomotor activities were evaluated on days 1,7, and 14 using open field test (OFT). Then, food consumption and BWD were measured.

 The sub-chronic consumption of sucrose and white chocolate significantly decreased total crossing number of OFT compared to control group. Moreover, acute consumption of sucrose tended to significant decreases in central crossing number. The sub-chronic dark chocolate consumption showed a significant enhancement of central crossing number. In different mono-diet of nutrients, the food consumption showed significant decreases in all groups compared to control group. The BWD had significant decreases in the first seven days. In addition, The BWD showed significant decreases in sucrose, milk chocolate, and dark chocolate during the final seven days.

 Anxiety significantly decreased by sub-chronic consumption of dark chocolate and acute sucrose consumption. Moreover, sub-chronic sucrose and white chocolate consumption decreased locomotor activity in subjects. While, regardless of nutrient types, the mono-diet could cause major weight loss. Further weight loss occurred with a high concentration of cocoa in the dark chocolate mono-diet.

The periaqueductal gray (PAG) region plays an essential role in the modulation of nociception. Also, lateral PAG (lPAG) is involved in reward circuitry by the dopaminergic system in addiction. The present study investigated the blockade of D1/D2-like dopamine receptors in the lateral PAG region affects morphine self-administration with and without exercise.

Rats were divided into six groups. The rats were initially trained to receive small pellets of food by pressing an active lever in the self administration apparatus. Exercise groups were run on a treadmill at 20m/min, 5 days/week, for 4 weeks before the surgery. Then rats were bilaterally implanted with cannulae in lPAG. The SCH23390 and sulpiride were microinjected into the lPAG, 5min before receiving morphine. Afterward, the animals were allowed to self administer morphine in 2h sessions over 11 consecutive days. At last, the numbers of lever pressing, infusion times and withdrawal symptoms were measured.

The results showed the number of active lever pressing was significantly increased in the morphine group compared to other groups in self-infusion during 11 days. Exercise significantly reversed the detrimental effects of morphine self-administration after five days. However, the synergistic effect of injected sulpiride into the lPAG region with exercise training was more pronounced on the amelioration of morphine than on the combinatory effect of SCH23390 with exercise.

The findings suggested that the D2 dopamine receptor in the lPAG region was involved in the morphine addiction via the dopaminergic system and exercise training in combination with antagonists could reduce the rewarding properties of morphine.

The nucleus basalis magnocellularis (NBM) sends projections to the hippocampus that are implicated in learning and memory formation. Despite ample evidence proposing that cognitive function impairment related to neurodegeneration, it may result from alteration of biochemical substances. We aimed to investigate the effects of NBM lesions on the hippocampal interleukin-1beta (IL-1β), brain-derived neurotrophic factor (BDNF), and corticosterone levels, as inflammation markers, and hallmarks of neurodegeneration, stress, and metabolic status.

Thirty-six male Wistar rats were randomly put in control, sham, and NBM-lesioned groups. After inducing the lesion using an intra-NBM injection of 10 μg ibotenic acid (5 μg/μL, each side) in rats, memory was estimated using the passive avoidance test. Moreover, serum and hippocampal IL-1β levels, as well as the hippocampal corticosterone, BDNF, and glucose levels were measured after 42 days.

Findings indicated a significant impairment of retention at different intervals in the NBM-lesioned group. BDNF decreased whereas corticosterone, glucose, and IL-1β levels increased in the hippocampus. Also, the levels of serum IL-1β, hippocampal BDNF, corticosterone, and glucose had significant correlations with hippocampal IL-1β levels.

The synchronous alterations of some hippocampal factors, including BDNF, corticosterone, IL-1β, and glucose, caused by NBM lesion suggest that their interaction might play a significant role in neurodegeneration and relevant learning and memory impairments

Corticotropin-Releasing Hormone (CRH) is involved in stress and energy homeostasis. On the other hand, CRH receptors also exist within the paraventricular nucleus (PVN) and Central Amygdala (CeA) nuclei. The present study compared the effect of CRH microinjections into PVN and CeA on three consecutive hours and cumulative food intake, internal regulatory factors of food intake, such as serum leptin and ghrelin, as well as blood glucose levels in rats under different acute psychological (Social Stress [SS] and Isolation Stress [IS] group) stresses.

Sixty-six male Wistar rats were randomly allocated to 11 groups: Control, Sham, CRH-PVN, CRH-CeA, SS, IS, SS-CRH-PVN, SS-CRH-CeA, IS-CRH-PVN, and IS-CRH-CeA groups. The CRH (2 µg/kg in 0.5 µL saline) was injected into PVN and CeA nuclei in rats under everyday, acute social stress and isolation stress conditions. 

Acute isolation and social stresses did not affect cumulative food intake. Whereas isolation stress led to changes in both leptin and glucose levels, social stress reduced only glucose levels. Cumulative food intake significantly decreased under acute CRH injection into the CeA and particularly into the PVN. Blood glucose significantly reduced in all the groups receiving CRH into their CeA. 

The PVN played a more important role compared to CeA on food intake. These nuclei probably employ different mechanisms for their effects on food intake. Besides, it seems that exogenously CRH injection into the PVN probably had a more anorectic effect than naturally activated CRH by stresses. Acute isolation stress had a greater impact than social stress on leptin level and cumulative food intake. Thus, elevated food intake related to leptin compared to ghrelin and glucose levels in the CRH-PVN group under acute social stress.

One of the problems of addiction treatment is the relapsing of withdrawal syndrome signs in the addicted person. Rewarding brain regions such as medial prefrontal cortex (mPFC) and ventral tegmental area (VTA) are involved in addiction and onset of withdrawal syndrome. This study was performed to investigate the relationship between these areas in demonstration or relief of withdrawal signs, electrical stimulation and lesion of mPFC, as well as blocking the relative receptors in the VTA.

In an experimental study, 42 male rats weighing 250-300 g were divided in 6 equal groups of control, morphine, and stimulation and lesion electrical receiver groups in mPFC region, and groups receiving the glutamate receptors antagonists by microinjection into the VTA. All of the groups, except the control group, received intraperitoneal morphine during 9 days as the protocol. Finally, on the 10th</sup> day, the symptoms of addiction in rats were evaluated.

The electrical stimulation of mPFC significantly increased cycling and scratching (P < 0.01) and bodylifting (P < 0.05) in comparison to the morphine group. Whereas the lesion of this area, and also microinjection of glutamate antagonists into the VTA caused significant decrease of all the withdrawal symptoms in rats.

Electrical stimulation of mPFC area increased the withdrawal symptoms in addicted rats, which was most likely due to increase of glutamatergic transmissions into the VTA and reinforcement of reward system; while destruction of this area and blocking of glutamate receptors, probably via decreasing of glutamatergic transmissions, caused decrease of morphine addiction.

Stress influences cognitive behavior adversely, whereas dark chocolate exhibits positive effects on memory processes. This study investigated the effects of different dark chocolate diets on various aspects of brain functions in rats under chronic stress

Thirty-five rats were randomly allocated into five groups: control, stress, stress with different (compulsory, optional and restricted) dark chocolate diets. Latency, dark stay (DS) time and the number of entrance to the dark compartment were respectively evaluated as memory, memory consolidation and locomotor activity by passive avoidance test.

There were significant differences between initial latency and latency after 1 day in all groups. In the stress-compulsory and restricted dark chocolate diet groups, latency after 1 day increased significantly. Moreover, the DS time was not significantly higher in the stressed group than the control group. The DS time and number of entrance to dark compartment decreased significantly in the stress-compulsory dark chocolate diet group compared to the stressed group. Furthermore, the number of entrance to dark compartment was significantly higher for the stress- optional dark chocolate diet compared to those with the compulsory diet. Additionally, serum and hippocampal corticosterone levels, except in the frontal cortex, were significantly lower only in the stress-compulsory dark chocolate diet group compared to the stressed group.

Different dark chocolate diets had various effects on brain functions under chronic stress. Respectively, the compulsory and optional dark chocolate diets had the best and least effects on brain function improvement. Only the compulsory dark chocolate diet could improve brain functions such as memory, memory consolidation and locomotor activity.

Chronic stress impairs memory and certain brain functions such as locomotor activity. Crocin is one of the active components of saffron and has neuroprotective effects on brain functions. This study investigated crocin effects on locomotor activity and recognition of new conditions (exploration time) as well as novel object recognition and object location memories in chronic restraint stress rats.

Thirty-two male Wistar rats were randomly allocated to control group, restraint stress group (6h/day for 21days) and two groups receiving daily intraperitoneal injections of crocin (30 and 60mg/kg) accompanied by restraint stress. Memories were evaluated using the relevant novel object recognition (NOR) and object location (OLT) tests.

The NOR and OLT results, respectively, revealed significant and non-significant decreases in locomotor activity in the stressed group. The NOR results revealed enhanced locomotor activity due to crocin administration (30 and 60mg/kg). The NOR revealed significant enhancements in recognizing new conditions in both crocin treatments while the OLT test did so only with a crocin dose of 60mg/kg. Restraint stress and crocin treatments led to no significant differences in novel object recognition and object location memories. Finally, the stressed group exhibited significant increases in serum corticosterone levels but corticosterone levels declined significantly with crocin dose of 30mg/kg.

The high and low doses of crocin had different effects on the NOR and OLT variables under restraint stress conditions. The NOR test as cognitive test was found more sensitive to crocin treatments than the OLT test as spatial test although neither the memories showed changes in response to such treatment.

Chronic liver disease frequently accompanied by hepatic encephalopathy (HE). Changes in the permeability of the blood-brain barrier in HE, make an easier entrance of ammonia among other substances to the brain, which leads to neurotransmitter disturbances. Lactulose (LAC), causes better defecation and makes ammonia outreach of blood. Silymarin (SM) is a known standard drug for liver illnesses. The purpose of this research was to determine the results of LAC and SM combined treatment, on the changes in memory of cirrhotic male rats.

The cirrhotic model established by treatment with thioacetamide (TAA) for 18 weeks. Cirrhotic rats randomized to four groups (n = 7): TAA group (received drinking water), LAC group (2 g/kg/d LAC in drinking water), SM group (50 mg/kg/d SM by food), SM+ LAC group (similar combined doses of both compounds) for 8 weeks. The control group received drinking water. The behavior examined by wire hanging (WH), passive avoidance (PA), and open field (OF) tests.

Our findings showed that treatment with SM+LAC effectively increased PA latency, compared with the control group. The results showed that the administration of LAC and SM+LAC affected the number of lines crossed, the total distance moved and velocity in the OF tests.

SM and LAC have anti-inflammatory effects that are memory changing. It may be due to their useful effects. These results indicated that SM+LAC restored memory disturbance and irritated mood in the cirrhotic rats. Comparable neuroprotection was never previously informed. Such outcomes are extremely promising and indicate the further study of SM+LAC.

Effects of chronic scheduled dietary on plasma ghrelin and food intake in adult male rats were assessed.

Forty male Wistar rats (180-200g) were distributed into four groups (n=10), freely fed rats (control) and three scheduled-fed groups with different caloric intakes: high fat, standard and restricted diet. Then, plasma ghrelin and food intake were measured on days 0, 7 and 14.

Plasma ghrelin was significantly different among all groups, the scheduled-standard rats having the lowest ghrelin on day 7 and the restricted rats having the highest ghrelin on day 14. Noteworthy, fasted ghrelin in controls was as much as that of schedule groups exception restricted diet at the end of experiment. Controls consumed stable food over the time, while schedule groups showed time and caloric-dependency of food intake. Schedule-standard and restricted groups on feeding time consumed high level of food. Schedule-high fat group displayed a time dependent reduction in food intake. A positive correlation was found between plasma ghrelin and food intake in fasting status for freely fed rats and anticipating status for standard and restricted-schedule groups.

A component of ghrelin secretion can be entrained or learned for time feeding as well as long last-fasting and more is affected by quantitative and qualitative of caloric intake. Elevated ghrelin levels in restricted model are subjective both by low energy levels and learning. Also, caloric intake amount can be controlled by learning; we observed a reduction in meal size in scheduled–high fat diet.</div>

Stress affects brain functions and induces psychological disorders. Previous studies have indicated different effects of crocin and exercise on the improvement of memory in some types of stress. The present study investigated the effect of crocin, exercise, and crocin‑accompanied exercise on learning, memory, and memory consolidation in rats under chronic unpredictable stress (CUS).

Male rats were randomly allocated to different groups: control, sham, stress, stress‑exercise, stress‑crocin, and stress‑crocin‑accompanied exercise groups. The CUS and treadmill running were applied 2 h/day and 1 h/day, respectively, for 21 days. Crocin (30 mg/kg) was daily intraperitoneally injected to the rats and their behavioral variables were evaluated as a brain function using the passive avoidance test.

Results showed that the CUS significantly decreased learning and memory compared to the control group, while crocin alone and crocin‑accompanied exercise significantly improved learning and memory compared to the stressed group. It was found that exercise alone caused learning but did not improve memory in unpredictable stress rats.

The data indicated that unpredictable stress had very destructive effects on the brain functions. Furthermore, unlike exercise, crocin improved memory under unpredictable stress conditions. Overall, it seems that the beneficial effects of crocin‑accompanied exercise on learning and memory were probably because of crocin, but not exercise.

Certain types of chronic mental stress impair memory. On the other hand, crocin is introduced in the medical literature as an effective component of saffron with remedial effects on memory impairment. This study investigated the effects of crocin on spatial and cognitive memories, locomotor activity, novel recognition conditions and serum corticosterone levels in rats under chronic isolation stress. Male rats were randomly allocated to the five groups of control, sham, isolation stress (St.I), St.I-C30 and St.I-C60. The latter two groups were exposed to chronic isolation stress (6h/day) receiving two levels of crocin (30 and 60 mg/kg, respectively) over a period of 21 days. The object location and novel object recognition tests (OLT and NOR) were used to evaluate spatial and cognitive memories, respectively. The OLT results revealed that chronic isolation stress led to significantly decreased locomotor activity in all the stressed groups; the NOR test, however, yielded similar results only in the St.I group. Moreover, isolation stress was found to lead significant declines in spatial and cognitive memories. Finally, crocin administration led to improvements in impaired memory in St.I-C30 and St.I-C60 groups. There were significant enhancements in serum corticosterone levels in the St.I and St.I-C30 groups as compared with the control group. Our findings indicate that spatial and cognitive memory impairments are strongly affected by isolation stress and crocin especially at its high dose of 60 mg/kg, exhibits better protective effects against cognitive memory deficit induced by chronic isolation stress.

Exposure to psychological stresses can be a reason for obesity. Therefore, identifying the effective nutritional mechanisms such as feeding markers is of high necessity for the psychological stress conditions. Hence, the present study investigates the effects of subchronic isolation and social stresses on food intake, body weight differences (BWD), and levels of leptin, ghrelin, and glucose in rats.

Eighteen male rats were randomly allocated into three groups: control (Co), isolation stress (IS), and social stress (SS) groups. Rats were under stresses for 7 days. The food intake (for three continuous hours after 16–18 h of food deprivation), BWD, levels of ghrelin, leptin, and glucose were measured.

The results showed that the food intake significantly (P < 0.05) reduced during the 1st h in the SS group compared to the Co group. At the 2nd h, the food intake significantly (P < 0.001 and P < 0.01, respectively) decreased in the IS group compared to the Co and SS groups. The cumulative food intake and body weight were significantly (P < 0.05) reduced in the IS group compared to the Co group. The serum ghrelin level significantly reduced in the IS group compared to the Co group.

The subchronic psychological stresses led to a reduction in food intake by the reduction of serum ghrelin levels. It seems that ghrelin might have a more fundamental role in the food intake with respect to the leptin and glucose levels in subchronic stress condition. Furthermore, the decreased body weight justified the reduction of food intake, particularly in subchronic isolation stress.

Exercise reverses retention deficit induced by morphine. The present study investigated the effect of aerobic exercise on tolerance to morphine usage and pain modulation.

Male Wistar rats were divided into four groups as follows: (1) saline group (S), (2) morphine group (M), (3) saline + exercise (S + E), and (4) morphine + exercise group (M + E). The rats were initially trained to receive small pellets of food by pressing an active lever in the self‑administration apparatus. The tail‑flick and hot‑plate tests were used for pain assessment. To perform the experiment, the jugular vein was exposed and cannulated. After recovery, the animals were placed in the self‑administration apparatus and allowed to self‑administer morphine in 2 h sessions over 11 consecutive days.

The morphine group was found to record a higher number of active lever pressings than did the saline one while this parameter decreased in the morphine + exercise group compared with the morphine one. Moreover, the morphine + exercise exhibited lowered pain sensitivity as evidenced to have reduced morphine use in the hot plate test.

The exercise might be suggested to reduce using of morphine and modulate pain probably through the release of endogenous opioid.

Psychological stresses influence brain functions such as learning and memory. Environmental factors like types and durations of stress affect brain responsiveness. This study investigated the effects of two subchronic social and isolation stresses on learning, memory, adrenal glands weight and corticosterone levels in the hippocampus and frontal cortex.
Eighteen male rats were randomly allocated into three experimental groups: control, social stress and isolation stress groups. Rats were under stresses for 7 days. Latency of entrance into the dark room was evaluated as brain function, using the passive avoidance test before inducing of electrical shock (as initial latency) and on days 1, 3, 5 and 7 after foot shock. In addition, corticosterone levels were measured in the homogenized hippocampus and frontal cortex.
The latencies of days 1, 3 and 5 were significantly lower in an isolation stress group than the control group. The latency of day 7 significantly decreased in social and isolation stress groups, compared to the control group. The adrenal glands weight showed significant enhancements in social and isolation stress groups, compared to the control group. Although, the weight of the adrenal glands significantly increased in an isolation stress group, compared to the social stress group. There was a significant enhancement in the corticosterone levels in the hippocampus, but not frontal cortex in isolation stress group.
It was concluded that subchronic isolation stress severely deteriorated brain functions (learning and memory) compared to the subchronic social stress. In addition, isolation stress affected corticosterone levels in the hippocampus more than frontal cortex.