Neuroscience letters
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Neuroscience letters · Mar 2013
Comparative StudyVoluntary resistance running induces increased hippocampal neurogenesis in rats comparable to load-free running.
Recently, we reported that voluntary resistance wheel running with a resistance of 30% of body weight (RWR), which produces shorter distances but higher work levels, enhances spatial memory associated with hippocampal brain-derived neurotrophic factor (BDNF) signaling compared to wheel running without a load (WR) [17]. We thus hypothesized that RWR promotes adult hippocampal neurogenesis (AHN) as a neuronal substrate underlying this memory improvement. Here we used 10-week-old male Wistar rats divided randomly into sedentary (Sed), WR, and RWR groups. ⋯ We found that even when the average running distance decreased by about half, the average work levels significantly increased in the RWR group, which caused muscular adaptation (oxidative capacity) for fast-twitch plantaris muscle without causing any negative stress effects. Additionally, immunohistochemistry revealed that the total BrdU-positive cells and newborn mature cells (BrdU/NeuN double-positive) in the dentate gyrus increased in both the WR and RWR groups. These results provide new evidence that RWR has beneficial effects on AHN comparable to WR, even with short running distances.
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Previous imaging studies have described gray and white matter alterations in the cerebellum, the posterior aspects of the visual system and in the corpus callosum in patients with schizophrenia. Here, we investigated these regions in more detail using tract-based spatial statistics (TBSS). Additionally, we evaluated potential changes in lateralization of the optic radiation and the superior cerebellar peduncle. ⋯ Our findings substantiate the concept that schizophrenia is a neurodevelopmental disorder and indicate that changes in lateralization may play a key role in the pathogenesis of this disease.
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Neuroscience letters · Mar 2013
COMT and MTHFR polymorphisms interaction on cognition in schizophrenia: an exploratory study.
The investigation of the catechol-O-methyltransferase (COMT-[rs4680]) and methylenetetrahydrofolate reductase (MTHFR-[rs1801133]) polymorphisms' interaction might shed light into the pathogenetic mechanisms of the cognitive dysfunction in schizophrenia. In an exploratory study, we hypothesized that the MTHFR 677T allele which has been related to a hypoactive MTHFR enzyme would augment the unfavorable effects of COMT Val158 homozygosity which has been associated with COMT enzyme hyperfunction. 90 schizophrenia patients and 55 healthy volunteers were assessed on psychomotor speed, pattern and spatial recognition memory (SRM), spatial working memory (SWM), attentional flexibility and planning (Stockings of Cambridge-SOC). IQ scores in a random subgroup of patients were also measured. ⋯ In conclusion, COMT and MTHFR polymorphisms interacted on cognition, suggesting that the MTHFR enzyme activity might moderate the effects of the COMT enzyme. In contrast to our initial hypothesis, the MTHFR T-allele attenuated the cognitive effects of COMT Val homozygosity. In this preliminary study, we propose that dopaminergic and intracellular methylation mechanisms could interact on cognitive deficits in schizophrenia.
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Neuroscience letters · Mar 2013
Comparative StudyBehavioral effects of repeated handling differ in rats reared in social isolation and environmental enrichment.
The post-weaning social environment has profound effects on behavior and physiology in rodents. Social isolation increases anxiety-like behaviors and novelty-induced locomotor activity, while environmental enrichment decreases these behaviors. In some cases, the effects of social isolation are ameliorated by repeated handling. ⋯ ISO rats exhibited significantly fewer stereotyped behaviors than did EE rats, but repeated handling eliminated this difference. These findings support previously published studies that suggest brief handling of adult rats may at least partially ameliorate the effects of post-weaning social isolation on anxiety-like behaviors and psychostimulant sensitivity. Furthermore, there are complex interactions between the effects of housing environment and handling, suggesting that handling may be perceived and/or processed differently, depending on the animal's housing environment.
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Neuroscience letters · Mar 2013
Signal flow and pathways in response to early Wallerian degeneration after rat sciatic nerve injury.
Wallerian degeneration (WD) remains a subject of critical research interest in modern neurobiology. WD is a process which a large number of genes are differentially regulated, especially the early response to activate nerve degeneration and regeneration, but the precise mechanisms remain elusive. ⋯ KEGG pathway analysis revealed activity mainly relating to cytokine-cytokine receptor interaction, MAPK signaling pathway, Jak-STAT signaling pathway, ErbB signaling pathway and TGF-beta signaling pathway involved in the recurrent neural networks that were regulated by the key factors, Cldn-14, Cldn-15, ITG, BID and BIRC3. These results will help to much better understand information relating to the early response to WD and provide us with a firmer basis in future investigations on the molecular mechanisms of WD that regulate nerve degeneration and/or regeneration.