Environmental enrichment improves cognitive deficits in Spontaneously Hypertensive Rats (SHR): Relevance for Attention Deficit/Hyperactivity Disorder (ADHD)

The interaction between genes and environment seems to be relevant for the development of Attention Deficit/Hyperactivity Disorder (ADHD), one of the most prevalent childhood psychiatric diseases. The occurrence of ADHD is typically associated with poor academic performance, probably reflecting learning difficulties and/or cognitive impulsiveness. The inbred Spontaneously Hypertensive Rats (SHR) strain has often been considered as an animal model of ADHD, since they ‘naturally’ display the main ADHD symptomatology. Although pharmacological agents improve SHR's cognitive deficits, little is known about the involvement of environmental factors in SHR disabilities and to what extent ‘protective’ non-pharmacological factors may be considered as strategy for ADHD prevention. Here we investigated whether the rearing environment during neurodevelopment may counteract later cognitive deficits presented by adult SHR. Wistar (WIS) rats were also used to investigate whether the putative effects of environmental enrichment depend on a specific genetic background. The animals were reared in enriched environment (EE) or standard environment (SE) from the post-natal day 21 until 3 months of age (adulthood) and tested for cognitive and non-cognitive phenotypes. EE improved SHR's performance in open field habituation, water maze spatial reference, social and object recognition tasks, while non-cognitive traits, such as nociception and hypertension, were not affected by EE. Response of WIS rats was generally not affected by the present EE. These results show that the general low cognitive performance presented by SHR rats strongly depends on the rearing environment and they may suggest modifications of the familial environment as a putative preventive strategy to cope with ADHD.     

大孔吸附树脂富集纯化珠子参总皂苷的工艺研究

目的:建立大孔吸附树脂富集、纯化珠子参总皂苷的最佳工艺条件。方法:以人参皂苷Re为对照,以总皂苷含量为指标,研究了HPD型大孔树脂吸附和纯化珠子参总皂苷的工艺条件。结果:优化的工艺条件为:样品溶液的浓度为0.13g/mL(生药量/体积);树脂用量为生药量的2倍(质量比);纯化先用水洗至α-萘酚反应呈阴性,改用6BV的60%乙醇洗脱,洗脱速度为2BV/min。结论:HPD-100型非极性大孔树脂对珠子参总皂苷有良好的吸附及纯化性能;本工艺对珠子参总皂苷的纯化收率高且稳定,纯化后总皂苷含量可达60%以上。     

The Influence of Facilitator and Facilitation Characteristics on Participants' Ratings of Stepfamily Education

We examine the relative importance of facilitator and facilitation characteristics on participant ratings of a stepfamily education program. Data from 48 facilitators and 598 participants suggest that quality facilitation is more meaningful to participants than whether facilitators have comparable demographic characteristics or life experiences. Hierarchical regressions identified time management effective use of personal experiences, and clear explanation of material as key facilitation skills. Popular assumptions about participant‐facilitator similarity and implications for programming are discussed.     

Neurobehavioral effects of environmental enrichment and drug abuse vulnerability

Environmental enrichment during development produces a host of neurobehavioral effects in preclinical models. Early work demonstrated that enrichment enhances learning of a variety of behavioral tasks in rats and these changes are associated with neural changes in various cortical regions. In addition to promoting superior learning, more recent evidence suggests that environmental enrichment also has a protective effect in reducing drug abuse vulnerability. The current review describes some of the most important environment-dependent neural changes in reward-relevant brain structures and summarizes some of the key findings from the extensive literature showing how enrichment decreases the impact of drugs of abuse. Some critical neural mechanisms that may mediate the behavioral changes are postulated, along with some notes of caution about the limitations of the work cited.     

17β-estradiol and enriched environment accelerate cognitive recovery after focal brain ischemia

Cognitive impairments, including spatial memory and learning deficiencies, are common after ischemic stroke. Estrogen substitution improves cognitive functions in post-menopausal women and ovariectomized rodents, partially through induction of neuroplasticity in the hippocampal formation. Post-ischemic housing of male rats in an enriched environment (EE) improves functional outcome, without changing infarct volume. We hypothesized that 17β-estradiol combined with an EE would accelerate cognitive recovery after focal brain ischemia in ovariectomized rats and that recovery would be related to altered expression of nerve growth factor-induced gene (NGFI)-A in the hippocampus. 17β-estradiol or placebo pellets were implanted 6 h after transient middle cerebral artery occlusion. Two days later, rats were placed in an EE or a deprived environment (DE) for 6 weeks. At 5 weeks after middle cerebral artery occlusion, 17β-estradiol-treated rats housed in an EE showed improvements in cognitive function (i.e. shorter latency and path in the Morris water maze task) compared with placebo-treated animals housed in an EE. Furthermore, beneficial effects on latency and path were observed when comparing EE-housed vs. DE-housed 17β-estradiol-treated rats. When comparing 17β-estradiol-treated EE-housed rats vs. placebo-treated DE-housed rats, pronounced effects on latency and path were observed. Infarct volumes did not differ between groups. 17β-estradiol-treated EE-housed rats had significantly higher NGFI-A mRNA expression bilaterally in the cornu ammonis 1 region and in the ipsilateral dentate gyrus of the hippocampus, compared with placebo-treated EE-housed rats. In conclusion, 17β-estradiol treatment combined with an EE improved recovery of cognitive function after experimental brain ischemia, putatively through the upregulation of NGFI-A in hippocampal subregions.     

A sensitive period for environmental regulation of eating behavior and leptin sensitivity

Western lifestyle contributes to body weight dysregulation. Leptin down-regulates food intake by modulating the activity of neural circuits in the hypothalamic arcuate nucleus (ARC), and resistance to this hormone constitutes a permissive condition for obesity. Physical exercise modulates leptin sensitivity in diet-induced obese rats. The role of other lifestyle components in modulating leptin sensitivity remains elusive. Environmentally enriched mice were used to explore the effects of lifestyle change on leptin production/action and other metabolic parameters. We analyzed adult mice exposed to environmental enrichment (EE), which showed decreased leptin, reduced adipose mass, and increased food intake. We also analyzed 50-d-old mice exposed to either EE (YEE) or physical exercise (YW) since birth, both of which showed decreased leptin. YEE mice showed no change in food intake, increased response to leptin administration, increased activation of STAT3 in the ARC. The YW leptin-induced food intake response was intermediate between young mice kept in standard conditions and YEE. YEE exhibited increased and decreased ratios of excitatory/inhibitory synapses onto α-melanocyte-stimulating hormone and agouti-related peptide neurons of the ARC, respectively. We also analyzed animals as described for YEE and then placed in standard cages for 1 mo. They showed no altered leptin production/action but demonstrated changes in excitatory/inhibitory synaptic contacts in the ARC similar to YEE. EE and physical activity resulted in improved insulin sensitivity. In conclusion, EE and physical activity had an impact on feeding behavior, leptin production/action, and insulin sensitivity, and EE affected ARC circuitry. The leptin-hypothalamic axis is maximally enhanced if environmental stimulation is applied during development.     

Environmental enrichment reduces mechanical hypersensitivity in neuropathic mice,but fails to abolish the phenotype of CCK2 receptor deficient mice

Genetic invalidation of CCK₂ receptors abolishes chronic constriction injury (CCI) induced mechanical hypersensitivity in mice. However, housing in environmentally enriched conditions significantly alters the phenotype of CCK₂ receptor deficient mice in all major behavioral domains. Furthermore, environmental enrichment itself has been reported to have protective effects in several rodent models of neurological diseases (brain and spinal trauma, ischemic stroke, Alzheimer's disease, etc.). In the present study we reproduced the earlier finding that mice, lacking CCK₂ receptors (−/−) are resistant to CCI-induced hypersensitivity. On the other hand, environmental enrichment substantially reduced CCI-induced mechanical hypersensitivity in wild-type (+/+) mice. Nevertheless, the phenotypic differences between wild-type (+/+) and mutant (−/−) mice in mechanical sensitivity before and after CCI-surgery were not eliminated by alternative housing conditions. These observations suggest that environmental enrichment has beneficial effects in neuropathic conditions and reinforce the causal link between CCK₂ receptors, mechanical sensitivity and the development of CCI-induced hypersensitivity.     

Environmental enrichment enhances directional selectivity of primary auditory cortical neurons in rats

Environment enrichment (EE) has an important role in brain plasticity. Previous research has shown that EE increases the response strength of auditory cortical neurons, but it remains unknown whether EE can affect the directional selectivity of auditory neurons. In this study, rats were exposed to EE conditions during the developmental critical period (EE1) or after the critical period (EE2). By in vivo extracellular recording, we found that EE enhanced the directional selectivity of primary auditory cortical neurons in EE1 rats, which showed a sharper azimuth selectivity curve of auditory cortical neurons compared with normal rats. However, there was no significant difference in directional selectivity between the EE2 rats and age-matched control rats. Our findings indicate that early exposure to EE enhances the directional sensitivity of primary auditory cortical neurons. These results provide an insight into developmental plasticity in the auditory system.     

杠柳不同部位无机元素的分布及富集特征研究

[目的] 测定3种植物形态(藤本、灌木、蔓生灌木)杠柳根皮、茎皮、根际土壤中Mn、Cu、Zn、Fe、K、Ca、Mg共7种元素的含量,考察杠柳不同部位各元素的分布及富集特征.[方法] 电热板湿法消解样品,火焰原子吸收法测定各元素含量.[结果] 根皮、茎皮中各元素含量差异较大,但大小顺序均为K > Ca > Mg > Fe > Mn > Cu > Zn;元素Zn、Fe、K、Ca在两部位中的分布具较明显差异性,Zn、K、Ca在茎皮中有较多分布,而根皮中有更多的Fe;根际土壤中元素含量大小顺序为Fe > K > Ca > Mg > Mn > Zn > Cu,杠柳生长土壤质量较优;根皮、茎皮对Cu、Ca富集性较强,K在茎皮中有一定的富集.[结论] 明确了杠柳根皮、茎皮中7种元素的含量、分布及富集特征,提供了杠柳植物形态分为两类的数据支撑,首次提出杠柳作为铜污染区土壤修复植物的可能性,为完善杠柳的生态学等基础研究奠定了基础.