ABSTRACT
Adverse experiences in early life have long-lasting negative impacts on behavior and the brain in adulthood, one of which is sleep disturbance. As the corticotropin-releasing hormone (CRH)-corticotropin-releasing hormone receptor 1 (CRHR1) system and nucleus accumbens (NAc) play important roles in both stress responses and sleep-wake regulation, in this study we investigated whether the NAc CRH-CRHR1 system mediates early-life stress-induced abnormalities in sleep-wake behavior in adult mice. Using the limited nesting and bedding material paradigm from postnatal days 2 to 9, we found that early-life stress disrupted sleep-wake behaviors during adulthood, including increased wakefulness and decreased non-rapid eye movement (NREM) sleep time during the dark period and increased rapid eye movement (REM) sleep time during the light period. The stress-induced sleep disturbances were accompanied by dendritic atrophy in the NAc and both were largely reversed by daily systemic administration of the CRHR1 antagonist antalarmin during stress exposure. Importantly, Crh overexpression in the NAc reproduced the effects of early-life stress on sleep-wake behavior and NAc morphology, whereas NAc Crhr1 knockdown reversed these effects (including increased wakefulness and reduced NREM sleep in the dark period and NAc dendritic atrophy). Together, our findings demonstrate the negative influence of early-life stress on sleep architecture and the structural plasticity of the NAc, and highlight the critical role of the NAc CRH-CRHR1 system in modulating these negative outcomes evoked by early-life stress.
Subject(s)
Animals , Mice , Corticotropin-Releasing Hormone/metabolism , Nucleus Accumbens/metabolism , Receptors, Corticotropin-Releasing Hormone/metabolism , Sleep , Sleep Wake Disorders , Stress, Psychological/complicationsABSTRACT
Trace amines are endogenous molecules distributed in the central nervous system and peripheral tissues that resemble common biogenic amines in terms of subcellular localization, chemical structure, and metabolism. Trace amine-associated receptor (TAAR) is a kind of evolutionarily conserved G-protein-coupled receptors in vertebrates, in which TAAR1 is a functional regulator of monoamine transmitters such as dopamine and serotonin. TAAR1 is widely considered as a potential therapeutic target for schizophrenia, depression and drug addiction. Moreover, TAAR1 is also expressed in peripheral tissues. The homeostasis imbalance of trace aminergic system can induce over-activation of peripheral immune system and central immune inflammatory response. TAAR1 modulators are becoming potential emerging drugs for the treatment of immune-related illnesses, because they may play a major role in the activation or modulation of immune response.
Subject(s)
Animals , Humans , Receptors, G-Protein-Coupled/metabolism , Biogenic Amines , Dopamine , Substance-Related DisordersABSTRACT
Chronic stress may disrupt the normal neurodevelopmental trajectory of the adolescent brain (especially the prefrontal cortex) and contribute to the pathophysiology of stress-related mental illnesses, but the underlying molecular mechanisms remain unclear. Here, we investigated how synaptic cell adhesion molecules (e.g., nectin3) are involved in the effects of adolescent chronic stress on mouse medial prefrontal cortex (mPFC). Male C57BL/6N mice were subjected to chronic social instability stress from postnatal days 29 to 77. One week later, the mice exposed to chronic stress exhibited impaired social recognition and spatial working memory, simplified dendritic structure, and reduced spine density in the mPFC. Membrane localization of nectin3 was also altered, and was significantly correlated with behavioral performance. Furthermore, knocking down mPFC nectin3 expression by adeno-associated virus in adolescent mice reproduced the stress-induced changes in behavior and mPFC morphology. These results support the hypothesis that nectin3 is a potential mediator of the effects of adolescent chronic stress on prefrontal structural and functional abnormalities.
ABSTRACT
Background@#Depression affects approximately 5% of elderly people and its etiology might be related to chronic stress exposure during neurodevelopmental periods. In this study, we examined the effects of adolescent chronic social stress in aged mice on depressive behaviors and the excitatory-inhibitory (E/I) balance in stress-sensitive regions of the brain.@*Methods@#Sixty-four adolescent, male C57BL/6 mice were randomly assigned to either the 7-week (from post-natal days 29 to 77) social instability stress (stress group, n = 32) or normal housing conditions (control group, n = 32). At 15 months of age, 16 mice were randomly selected from each group for a series of behavioral tests, including two depression-related tasks (the sucrose preference test and the tail suspension test). Three days following the last behavioral test, eight mice were randomly selected from each group for immunohistochemical analyses to measure the cell density of parvalbumin (PV+)- and calretinin (CR+)-positive gamma-aminobutyric-acid (GABA)ergic inhibitory inter-neurons, and the expression levels of vesicular transporters of glutamate-1 (VGluT1) and vesicular GABA transporter (VGAT) in three stress-sensitive regions of the brain (the medial pre-frontal cortex [mPFC], hippocampus, and amygdala).@*Results@#Behaviorally, compared with the control group, adolescent chronic stress increased depression-like behaviors as shown in decreased sucrose preference (54.96 ± 1.97% vs. 43.11 ± 2.85%, t(22) = 3.417, P = 0.003) and reduced latency to immobility in the tail suspension test (92.77 ± 25.08 s vs. 33.14 ± 5.95 s, t(25) = 2.394, P = 0.025), but did not affect anxiety-like behaviors and pre-pulse inhibition. At the neurobiologic level, adolescent stress down-regulated PV+, not CR+, inter-neuron density in the mPFC (F(1, 39) = 19.30, P < 0.001), and hippocampus (F(1, 42) = 5.823, P = 0.020) and altered the CR+, not PV+, inter-neuron density in the amygdala (F(1, 28) = 23.16, P < 0.001). The VGluT1/VGAT ratio was decreased in all three regions (all F > 10.09, all P < 0.004), which suggests stress-induced hypoexcitability in these regions.@*Conclusions@#Chronic stress during adolescence increased depression-like behaviors in aged mice, which may be associated with the E/I imbalance in stress-sensitive brain regions.
ABSTRACT
Background@#Exposure to adverse experiences in early life may profoundly reshape the neurodevelopmental trajectories of the brain and lead to long-lasting behavioral and neural alterations. One deleterious effect of early-life stress that manifests in later life is sleep disturbance, but this has not been examined in aged mice and the underlying neural mechanisms remain unknown. Considering the important role of the nucleus accumbens (NAc) in the sleep-wake regulation, this study aimed to assess the effects of early-life stress on the sleep behaviors in aged mice and the potential involvement of the NAc in stress-induced sleep abnormalities.@*Methods@#Twenty aged male C57BL/6 mice (>16 months, n = 10 per group) were used in this study. During post-natal days 2 to 9, dams were provided with either sufficient (control) or a limited nesting and bedding materials (stressed). When the mice were 16 to 17 months old, their sleep-wake behaviors were recorded over 24 h using electroencephalogram and electromyelogram. The amount of each sleep-wake stage, mean duration, and stage transition was analyzed. Then, five animals were randomly chosen from each group and were used to measure the expression levels of vesicular glutamate transporter-1 (VGluT1) and vesicular transporters of γ-aminobutyric acid (VGAT) in the NAc using immunohistochemistry. Group comparisons were carried out using Student t test or analysis of variances when appropriate.@*Results@#Compared with the control mice, the early-life stressed aged mice spent less time awake over 24 h (697.97 ± 77.47 min vs. 631.33 ± 34.73 min, t17 = 2.376, P = 0.030), accordingly, non-rapid eye movement sleep time was increased (667.37 ± 62.07 min vs. 723.54 ± 39.21 min, t17 = 2.326, P = 0.033) and mean duration of rapid eye movement sleep was prolonged (73.00 ± 8.98 min vs. 89.39 ± 12.69 min, t17 = 3.277, P = 0.004). Meanwhile, we observed decreased VGluT1/VGAT ratios in the NAc in the stressed group (F(1, 16) = 81.04, P < 0.001).@*Conclusion@#Early adverse experiences disrupt sleep behaviors in aged mice, which might be associated with the excitatory-inhibitory imbalance in the NAc.
ABSTRACT
BACKGROUND@#Exposure to adverse experiences in early life may profoundly reshape the neurodevelopmental trajectories of the brain and lead to long-lasting behavioral and neural alterations. One deleterious effect of early-life stress that manifests in later life is sleep disturbance, but this has not been examined in aged mice and the underlying neural mechanisms remain unknown. Considering the important role of the nucleus accumbens (NAc) in the sleep-wake regulation, this study aimed to assess the effects of early-life stress on the sleep behaviors in aged mice and the potential involvement of the NAc in stress-induced sleep abnormalities.@*METHODS@#Twenty aged male C57BL/6 mice (>16 months, n = 10 per group) were used in this study. During post-natal days 2 to 9, dams were provided with either sufficient (control) or a limited nesting and bedding materials (stressed). When the mice were 16 to 17 months old, their sleep-wake behaviors were recorded over 24 h using electroencephalogram and electromyelogram. The amount of each sleep-wake stage, mean duration, and stage transition was analyzed. Then, five animals were randomly chosen from each group and were used to measure the expression levels of vesicular glutamate transporter-1 (VGluT1) and vesicular transporters of γ-aminobutyric acid (VGAT) in the NAc using immunohistochemistry. Group comparisons were carried out using Student t test or analysis of variances when appropriate.@*RESULTS@#Compared with the control mice, the early-life stressed aged mice spent less time awake over 24 h (697.97 ± 77.47 min vs. 631.33 ± 34.73 min, t17 = 2.376, P = 0.030), accordingly, non-rapid eye movement sleep time was increased (667.37 ± 62.07 min vs. 723.54 ± 39.21 min, t17 = 2.326, P = 0.033) and mean duration of rapid eye movement sleep was prolonged (73.00 ± 8.98 min vs. 89.39 ± 12.69 min, t17 = 3.277, P = 0.004). Meanwhile, we observed decreased VGluT1/VGAT ratios in the NAc in the stressed group (F(1, 16) = 81.04, P < 0.001).@*CONCLUSION@#Early adverse experiences disrupt sleep behaviors in aged mice, which might be associated with the excitatory-inhibitory imbalance in the NAc.
ABSTRACT
BACKGROUND@#Depression affects approximately 5% of elderly people and its etiology might be related to chronic stress exposure during neurodevelopmental periods. In this study, we examined the effects of adolescent chronic social stress in aged mice on depressive behaviors and the excitatory-inhibitory (E/I) balance in stress-sensitive regions of the brain.@*METHODS@#Sixty-four adolescent, male C57BL/6 mice were randomly assigned to either the 7-week (from post-natal days 29 to 77) social instability stress (stress group, n = 32) or normal housing conditions (control group, n = 32). At 15 months of age, 16 mice were randomly selected from each group for a series of behavioral tests, including two depression-related tasks (the sucrose preference test and the tail suspension test). Three days following the last behavioral test, eight mice were randomly selected from each group for immunohistochemical analyses to measure the cell density of parvalbumin (PV)- and calretinin (CR)-positive gamma-aminobutyric-acid (GABA)ergic inhibitory inter-neurons, and the expression levels of vesicular transporters of glutamate-1 (VGluT1) and vesicular GABA transporter (VGAT) in three stress-sensitive regions of the brain (the medial pre-frontal cortex [mPFC], hippocampus, and amygdala).@*RESULTS@#Behaviorally, compared with the control group, adolescent chronic stress increased depression-like behaviors as shown in decreased sucrose preference (54.96 ± 1.97% vs. 43.11 ± 2.85%, t(22) = 3.417, P = 0.003) and reduced latency to immobility in the tail suspension test (92.77 ± 25.08 s vs. 33.14 ± 5.95 s, t(25) = 2.394, P = 0.025), but did not affect anxiety-like behaviors and pre-pulse inhibition. At the neurobiologic level, adolescent stress down-regulated PV, not CR, inter-neuron density in the mPFC (F(1, 39) = 19.30, P 10.09, all P < 0.004), which suggests stress-induced hypoexcitability in these regions.@*CONCLUSIONS@#Chronic stress during adolescence increased depression-like behaviors in aged mice, which may be associated with the E/I imbalance in stress-sensitive brain regions.
ABSTRACT
<p><b>OBJECTIVE</b>To compare the clinical effects and clinical indications between Mobi-C cervical artificial disc replacement (CADR) and MC+ anterior cervical decompression and fusion(ACDF) in treating cervical spondylosis.</p><p><b>METHODS</b>The clinical data of 100 patients with cervical spondylosis treated ACDF or CADR from June 2009 to June 2015 were retrospectively analyzed. There were 53 males and 47 females, aged from 38 to 70 years old. Among them, 50 cases were treated by ACDF (ACDF group), follow-up time was for 22 to 42 months with an average of (32.24±5.20) months;other 50 cases were treated by CADR (CADR group), follow-up time was for 23 to 48 months with an average of (30.40±5.66) months. Odom criterion was used to evaluate the clinical effects in two groups. JOA score, including sensory function, motor function and bladder function was used to assess the spinal cord function. Preoperative and postoperative responsible intervertebral space heights, cervical curvatures were compared by image data between two groups.</p><p><b>RESULTS</b>All incisions obtained good healing and no serious complications were found. At final follow-up, 30 cases got excellent results, 12 good, 8 fair in ACDF group;and 34 cases got excellent results, 10 good, 6 fair in CADR group;there was no significant difference between two groups(u=4.000, =0.827). At final follow-up, the scores of sensory function and motor function were obviously improved(<0.05), and bladder function had not obviously recovered (>0.05) in two groups;and CADR group in the scores of sensory function and motor function were obviously better than of ACDF group(<0.05). There was no significant difference in preoperative intervertebral space height, cervical curvature between two groups, and at final follow-up both had different recovered. The recovery of CADR group was obviously better than of ACDF group.</p><p><b>CONCLUSIONS</b>CADR can quickly recover normal action for patients and retains the movement. CADR has certain advantages in recovering cervical curvature, improveing sensory function and motor function, but it is not able to completely replace ACDF.</p>
ABSTRACT
OBJECTIVE: To observe the impact of energy saving light,incandescent light and circadian light on the ethology of depressive rats and explore its possible mechanism on affecting the secretion of melatonin. METHODS: Thirty rats aged 6weeks were randomly selected from 40 specific pathogen free health female SD rats after they adapted to the living environment,depressive rat models were established in the rats by bilateral ovariectomy combined with isolated living and chronic unpredictable mild stress stimulation at the age of 11-14 weeks. Then these 30 ovariectomized rats were randomly divided into 3 intervention groups,including an energy saving light group,an incandescent light group and a circadian light group,with 10 rats in each group. The rats in these 3 groups were given specific experimental light intervention for 3 weeks respectively at the age of 17 weeks. The other 10 rats were raised in conventional environment as the control group. Their body weights were measured at the age of 17,19,20 and 21 weeks. The ethology tests were carried out by sucrose preference test and the open-field test at the age of 7,14 and 20 weeks respectively. The melatonin levels in peripheral blood of 7 time points from 19: 30 to 8: 30 were measured in the rats at age of 21 weeks. One rat in each group at every time point was randomly selected for examination. RESULTS: At the age of 17 weeks before light-intervention,the body weights of rats in 4 groups showed no significant difference( P > 0. 05). After light-intervention,at the age of 17-20 weeks,the body weights of rats in 3 intervention groups were gradually increased with the increase of age( P < 0. 05).There was no significant difference between body weights of rats at the age of 21 weeks and those at the age of 20 weeks in each group( P > 0. 05). At age of 7 weeks,no significant differences were found in sucrose consumption and standing scores among these 4 groups( P > 0. 05). After the depressive models were established,at the age of 14 weeks before light-intervention,in rats of these 3 intervention groups,the sucrose consumption and standing scores were lower than those of the control group( P < 0. 05),and there was no significant difference found in the above 2 indexes among these 3intervention groups( P > 0. 05). At the age of 20 weeks after light-intervention,the sucrose consumption and standing scores were not significantly different from each other among the 4 groups( P > 0. 05). The peak levels of melatonin in the peripheral blood of rats in these 3 intervention groups were higher than that in the control group. The peak levels onsets of melatonin in peripheral blood of rats in the circadian light group and the energy saving light group were earlier or 2 hours delayed compared to that of control group,while it was similar between the incandescent light group and control group.CONCLUSION: The circadian light,the energy saving light and the incandescent light are similarly effective in improving the behaviors of depressive rats. The circadian light can delay the onset of peak level of melatonin in peripheral blood.