Stress-induced impairment of inhibitory avoidance learning in female neuromedin B receptor-deficient mice

Neuromedin B (NMB) is a mammalian bombesin (BN)-like peptide that exerts its function via the neuromedin B receptor (NMB-R). The NMB/NMB-R system is involved in stress response, and therefore we examined behavioral properties in female mice lacking NMB-R using a restraint-induced stress paradigm. Thirty minutes of restraint in a wire mesh cage constituted a sufficient stress stimulus for mice as evidenced by elevated blood glucose concentrations in stressed wild-type and NMB-R-deficient mice. Using a one-trial passive avoidance test, stressed NMB-R-deficient mice exhibited a marked reduction in memory performance. NMB-R-deficient mice exhibited elevated spontaneous activity in a novel environment compared to non-stressed mutant mice after 30-min stress, and a similar difference was also observed between stressed/non-stressed wild-type mice. An elevated plus maze test showed that the stress stimulus had no effect on anxiety in either wild-type or NMB-R-deficient mice. Furthermore, pain response of wild-type and NMB-R-deficient mice induced by electric foot shock was not affected under either stressed or non-stressed conditions. These results indicate that impaired memory performance in stressed NMB-R-deficient mice is not a consequence of changes in spontaneous activity, anxiety, or pain response, and suggest that the NMB/NMB-R pathway may play a role in regulating the stress response via the neural system that controls learning and memory.     

Extensive training in a maze task reduces neurogenesis in the adult rat dentate gyrus probably as a result of stress

It has recently been shown that hippocampal neurogenesis can be modulated either directly or indirectly by ascending cholinergic inputs from the basal forebrain. In the present work, we sought to address whether extended training in a spatial navigation task would affect hippocampal neurogenesis in the presence of a severe and selective cholinergic depletion. Young female rats received stereotaxic injections of the immunotoxin 192 IgG-saporin into the basal forebrain nuclei and/or the cerebellar cortex. Starting from 4 to 5 weeks post-lesion, and for the subsequent 2 weeks, the animals were trained on paradigms of reference and working memory in the water maze and received single daily i.p. injections of bromodeoxyuridine (BrdU) at the end of each testing session. In line with previous observations, a dramatic 80% decrease in neuron proliferation was seen in the dentate gyrus of lesioned animals, as compared to vehicle-injected or intact controls. Interestingly, however, rats subjected to maze training over 2 weeks, irrespective of their learning success, exhibited significantly fewer newborn neurons than matched controls with no maze exposure. Thus, at least for the type of task used here, which has previously been shown to impose a certain degree of stress, extended training and learning does not appear to affect proliferation in the dentate gyrus.     

宫内缺氧对新生小鼠额叶皮质神经元内nNOS表达及对成年小鼠学习记忆能力的影响

为探讨孕鼠宫内缺氧对新生小鼠发育时期额叶皮质神经元内nNOS表达及对成年小鼠学习记忆能力的影响,本研究采用Tapanainen建立的缺氧模型致胎龄13、15、17d小鼠宫内缺氧,然后采用Nissl染色观察新生鼠发育时期P1、P7、P14、P28、P90额叶皮质内神经元的数量和形态变化;免疫组织化学染色方法观察新生鼠发育时期P1、P7、P14、P28、P90脑组织内nNOS阳性神经元的表达;Morris水迷宫实验检测P90小鼠的学习和记忆能力。结果显示:与正常组比较,宫内缺氧组小鼠额叶皮质神经元数量明显减少,额叶皮质神经元内nNOS的表达明显减弱。宫内缺氧组小鼠逃避潜伏期延长及穿环次数明显减少。以上结果提示宫内缺氧可导致新生鼠额叶皮质神经元数量明显减少及nNOS的表达也明显减弱,并引起成年小鼠学习记忆能力降低。     

Age and neurochemical correlates of radial maze performance in rats

Young adult (8 months) and aged (26 months) female Wister rats were tested in a 12-arm radial maze in which the optimal strategy was to enter all arms without a repetition. In order to determine if possible age-associated alterations in behavior were correlated with defects in cholinergic. GABAergic and adrenergic neurons in the hippocampus and cerebral cortex, the activities of choline acetyltransferase (CAT), glutamic acid decarboxylase (GAD) and tyrosine hydroxylase (TH) were assayed in these regions of all animals after testing in the radial maze. In the maze, the aged rats continued to perform at the chance level after 15 trials, whereas the young rats had virtually mastered the task. The only significant neurochemical age effect was an increase in hippocampal TH. However, analysis of individual differences among rats revealed positive correlations between maze performance and hippocampal CAT in the aged group and cortical GAD in both the young and aged groups.     

Learning in escape/avoidance tasks in female rats does not vary with reproductive condition

To determine whether the development of novel stimulus-response associations by the mother during the periparturient period is attributable to a general facilitation of learning produced by the hormonal milieu during that period, learning ability under various reproductive conditions was assessed in two tasks unrelated to the periparturitional situation. The two tasks, selected because they equalized the various groups for motivation and performance variables, were acquisition of a water-maze escape (including two reversals), and acquisition and retention of an unsignalled shuttlebox shock avoidance. The groups tested in the water maze were a midpregnant group, an immediately prepartum group, and an immediately postpartum group. In the shuttlebox, the same conditions (different rats) were compared, together with a nonpregnant estrus condition, and a nonpregnant diestrus condition. The results of both experiments indicate that although learning occurred, the characteristics of acquisition and retention were not influenced by reproductive condition.     

乌拉地尔对吗啡导致的大鼠空间记忆障碍的改善作用

目的研究吗啡对大鼠空间记忆的影响和5-HT1A受体激动剂乌拉地尔对这种影响的改善作用。方法;训练大鼠学习Morris水迷宫任务,检验它们在注射药物情况下回忆空间任务的能力。结果同时注射乌拉地尔(20mg/kg)和吗啡(10mg/kg)的大鼠通过回忆寻找Morris水迷宫隐蔽站台的潜伏期(第一次测验,30.43±9.46;第二次测验,41.00±10.30;单位,秒),显著短于单独注射吗啡的动物(第一次测验,87.00±22.53;第二次测验,96.67±20.85;均为P<0.01);而与对照组动物(第一次测验,16.17±3.74;第二次测验,16.33±2.36)没有显著差别。单因素方差分析对照组和给药情况下吗啡组、吗啡-纳洛酮组和吗啡-乌拉地尔组回忆测验结果分别为第一次测验,16.17±3.74、87.00±22.53、34.67±6.75、30.43±9.46,F1(3,21)=5.866,P<0.01;第二次测验,16.33±2.36、96.67±20.85、22.17±6.46、41.00±10.30,F2(3,21)=8.94,P<0.01。结论乌拉地尔能够显著改善吗啡导致的大鼠空间记忆障碍。     

Age-related working memory deficits in the allocentric place discrimination task: possible involvement in cholinergic dysfunction

It is well known that learning and memory ability declines with aging. Age-related long-term changes in learning and memory ability in rats were investigated with the place navigation task and the allocentric place discrimination task (APDT) in a water maze using the same animals for each task. In a working memory place navigation task, aged animals could learn the location of the platform as well as when they were young, although strategy shifts were observed. In contrast, accuracy in the APDT significantly declined from 90% to 65% with aging. This impairment was ameliorated by an acetylcholine esterase inhibitor physostigmine at 22–23 months old. No amelioration was, however, detected in the same animals tested when they further aged to 26–27 months old. These results suggest that the APDT performance is sensitive to age-related memory deficits and that this may be due to the cholinergic dysfunction.     

基于“互联网+”技术的上海市质子重离子医院资产管理的 探索和实践

针对医院资产管理的现状和难点,将平台中的空间管理同资产管理相结合,进行数据交互和功能拓展,不仅使医院空间和资产同步系统化、数据化,而且汇聚了资产管理全维度数据源,达到优化资源配置、降本增效的实践成果,也为建立基于云数据的资产设备全生命周期管理夯实基础。     

参仙汤改善多发性脑梗塞性痴呆大鼠学习记忆及其作用机制研究

目的：观察中药复方参仙汤对多发性脑梗塞性痴呆（简称MID）大鼠学习记忆的影响,并对其抗自由基损伤机制进行研究。方法：采用经左心注射 0.25 ml/kg 液体石蜡栓子造成 MID 大鼠模型,以水迷宫为学习记忆评价指标。通过对大鼠脑、肝组织超氧化物歧化酶（SOD）活力、丙二醛（MDA）和脂褐素（LF）含量测定,探讨参仙汤对抗脑缺血再灌注损伤的自由基损伤机制。结果：参仙汤大、中剂量组大鼠在水迷宫实验中作业时间、正确数得到提高（第5天,P<0.05 或P<0.001）。参仙汤大、中、小剂量组脑、肝组织 SOD 活力均有提高,MDA 和 LF 含量均有下降,脑组织尤为明显（P<0.01或P<0.001）。结论：参仙汤可能是通过抗脑缺血再灌注之自由基损伤,达到改善MID大鼠学习记忆功能的。     

Histologic and microbiological findings of the defunctionalized loop in sleeve gastrectomy with jejunal bypass

BackgroundBariatric surgery produces anatomic changes in the digestive tract that can affect the intestinal microbiome and, in some cases, can cause small intestinal bacterial overgrowth. Since the inception of the sleeve gastrectomy with jejunal bypass (SGJB) in 2004, there has been discussion regarding the possible development of those complications associated with the now abandoned jejunoileal bypass (JIB) procedure.ObjectivesThe primary endpoint was to characterize the bacteriologic and histopathologic findings in the defunctionalized jejunal loop after the SGJB procedure and to analyze the liver profile. The secondary endpoint was to report SGJB conversions or reversions and to review the differences between SGJB and JIB.SettingAcademic medical center.MethodsWe conducted a prospective study of patients who underwent laparoscopy for any reason, having previously had an SGJB. A 5-cm segment at the proximal end of the excluded limb was resected. Luminal liquid and tissue samples were taken from this segment for aerobic and anaerobic cultures, and pathologic examination of the bowel wall was performed to evaluate trophism and signs of chronic inflammation. Other variables were liver function and pre- and postoperative status. Finally, we retrospectively reviewed the causes of revisional surgery in the prospective database.ResultsEleven patients underwent laparoscopy. The median time after SGJB was 14 months (range, 10–144 months). There were no complications from the procedure. Eight (72.7%) of the procedures were cholecystectomies. None of the patients showed histologic alterations or signs of chronic infection. The liquid and tissue cultures were negative. The liver tests and the laparoscopic morphology of the liver were normal in all patients, except in 1 with previously documented liver cirrhosis. The number of SGJB revisions was 19 of 1074 (1.8 %), and all of them were converted to Roux-en-Y gastric bypass for severe gastroesophageal reflux.ConclusionsIn this study, we were unable to demonstrate the presence of symptoms or histologic alterations that would suggest that patients undergoing SGJB develop small intestinal bacterial overgrowth in the short- and medium-term follow-up, unlike those who have undergone JIB. The study constitutes an initial step toward establishing what happens to the defunctionalized jejunal limb as a result of this surgical technique.