脂多糖激活所致大鼠抑郁样行为及对海马神经细胞钾电流变化的影响

采用细胞因子刺激剂脂多糖(lipopolysaccharide,LPS)为免疫激活手段,研究LPS诱导的免疫激活产生的抑郁样行为及对海马神经细胞电压依赖钾电流变化的影响。应用膜片钳技术对海马神经细胞钾电流进行全细胞记录,比较抑郁样行为大鼠与正常大鼠钾离子通道电流密度和激活特性的变化。结果发现,与生理盐水对照组相比,一次LPS注射后2hr,实验组动物产生抑郁样行为,同时急性观察的海马神经细胞的钾离子通道的电流密度呈现显著升高(p<0.01);而一次LPS注射后24hr,动物的抑郁样行为消失,且急性观察的海马神经细胞的钾离子通道与对照组相比较,其电流密度和激活曲线没有显著性变化。结论:LPS诱导的抑郁样行为,与LPS诱导的海马神经细胞电压依赖钾电流的上调在时程上同步,提示钾离子通道可能参与免疫激活所致的抑郁样行为

Upregulation of K+ Current in Hippocampal Neurons from Rat with Depressive-Like Behavior Induced by

免疫激活所致大鼠抑郁样行为与海马神经细胞钾通道的研究 摘 要 抑郁症是危害人类健康的主要心理疾病之一，其病因机制至今未得到完全阐明。本工作研究免疫激活所诱发的抑郁样行为与海马神经细胞电压依赖型钾电流介导的细胞凋亡的关系。为系统探讨免疫激活对行为、海马神经细胞钾电流和神经细胞凋亡的影响及相互间的关系，本研究采用脂多糖（lipopolysaccharide, LPS）免疫激活诱导的抑郁样行为模型，应用膜片钳电压钳技术对在体的海马神经细胞钾电流进行全细胞记录, 比较抑郁样行为大鼠与正常大鼠的钾电流的变化；应用膜片钳电压钳技术对离体的海马神经细胞钾电流进行全细胞记录, 比较脂多糖组与正常组的钾电流的变化，对海马神经细胞动作电位进行全细胞记录，观察脂多糖组与正常组的动作电位的变化；应用DAPI（4&rsquo;, 6-diamidinophenylindole）染色观察法，观察脂多糖组与正常组的海马神经细胞凋亡的变化。 主要实验结果如下： 1. 一次脂多糖注射后2 hr，产生抑郁样行为；注射后24 hr，抑郁样行为消失。 2. 一次脂多糖注射后2 hr，急性观察的海马神经细胞的钾电流密度显著升高；慢性观察的海马神经细胞的钾电流密度和激活曲线没有显著性变化；注射后24 hr，急性观察的海马神经细胞的钾电流及电流密度和激活曲线没有显著性变化。 3. 脂多糖能诱导新生鼠海马神经细胞的钾电流密度显著升高，动作电位的时程明显变窄、动作电位的发放频率减少。但海马神经细胞的动作电位的幅度没有显著性的影响。 4. 脂多糖诱导海马神经细胞的凋亡率显著增加。 以上结果表明：脂多糖诱导的抑郁样行为，与电压依赖型钾电流上调及其介导的海马神经细胞凋亡有关。本研究的结果为抑郁症的炎性免疫假说提供了新的证据

Upregulation of K＋ Current in Hippocampal Neurons from Rat with Depressive-Like Behavior Induced by Lipopolysaccharide

采用细胞因子刺激剂脂多糖(lipopolysaccharide,LPS)为免疫激活手段,研究LPS诱导的免疫激活产生的抑郁样行为及对海马神经细胞电压依赖钾电流变化的影响。应用膜片钳技术对海马神经细胞钾电流进行全细胞记录,比较抑郁样行为大鼠与正常大鼠钾离子通道电流密度和激活特性的变化。结果发现,与生理盐水对照组相比,一次LPS注射后2hr,实验组动物产生抑郁样行为,同时急性观察的海马神经细胞的钾离子通道的电流密度呈现显著升高(p&lt;0.01);而一次LPS注射后24hr,动物的抑郁样行为消失,且急性观察的海马神经细胞的钾离子通道与对照组相比较,其电流密度和激活曲线没有显著性变化。结论:LPS诱导的抑郁样行为,与LPS诱导的海马神经细胞电压依赖钾电流的上调在时程上同步,提示钾离子通道可能参与免疫激活所致的抑郁样行为。;Lipopolysaccharide （LPS）-induced immunity activation can result in evident depressive-like behavior, such as anhedonia and reduced locomotion. Earlier studies have shown that K＋ channels, such as Kv7 and TREK-1, are involved in the development of depressive-like behavior in animal models. In the present study, we show that LPS （200 &mu;g/kg） could induce significant short-term depressive-like behavior in rat. In order to get insight into the underlying molecular mechanism, we investigated the potential involvement of rat hippocampal neuron voltage-dependent K＋ channels in the depressive-like behaviors induced by LPS. Methods： Twenty rats were randomly divided into LPS and control groups, each with ten rats. The rats in the LPS group were injected with LPS （200 ~tg/kg）, while saline was injected in the rats of the control group. The saccharin preference test and open field test were carried out 2 hours and 24 hours after injection of LPS to assess short-term or long-term effects on animal behavior, respectively. Next, 12 rats were randomly divided into LPS 2 hr, LPS 24 hr and control groups, each with four rats for assessing the effect of LPS on K＋ channel currents of hippocampal neurons by using whole-cell patch-clamp configuration. Results： The data showed that LPS induced depressive-like behavior in rat after 2 hours of single injection. However, this depressive-like behavior was recovered after 24 hours of single LPS injection. In agreement with these behavioral observations, voltage-dependent K＋ current density was increased in neurons isolated from rat after 2 hours of single LPS injection, whereas no significant change was found after 24 hours injection. Conclusion： Our results demonstrate that LPS-induced immunity activation can result in evident short term depressive-like behavior in rats, which are coincident with LPS induced up-regulation of voltage-dependent K＋ current in rat hippocampal neurons. This result suggests that voltage-dependent K＋ current might contribute to the development of the depressive-like behavior induced by LPS.</p

葛洲坝水库鱼类群落结构特征研究

2009～2010年的5～6月和11～12月在葛洲坝库区进行了鱼类资源调查,分析了鱼类群落结构特征。调查期间共收集到鱼类6目10科55种,其中鲤科物种数最多,占总种数的67.3%。5～6月和11～12月的鱼类群落结构组成、Shannon-Wiener多样性指数没有显著差异(P<0.05)。库区内优势种为贝氏、鳊、和蛇鮈,优势种个体较小,平均体长分别为91.4±15.7、219.7±35.3、86.7±16.0和102.5±22.3mm。分析发现,静水缓流型和江湖洄游型鱼类是葛洲坝库区主要的鱼类类群,分别占渔获物重量的50.2%和46.5%。丰度生物量比较曲线显示,葛洲坝库区鱼类群落结构受到中度干扰。根据生态类群分析,葛洲坝库区的鱼类群落结构与三峡库区相似,但与葛洲坝坝下江段和建坝前流水环境的鱼类群落结构相比,有明显的差异,说明水文条件变化对鱼类群落结构有明显的影响

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies