丁香酚对大鼠弓状核温度敏感神经元电活动的影响

本实验采用微电极细胞外记录技术,在大鼠弓状核记录到单一放电单位６８例,其中热敏神经元１１例,占１６．２％,冷敏神经元２５例,占３６．８％;温度不敏感神经元３２例,占５３％。本实验同时观察了皮下注射丁香酚（２０μｇ／１００ｇ）对温度敏感神经元放电活动的影响,其结果为１０例冷敏神经元的放电频率均减慢;４例热敏神经元的放电频率均增快;而１４例温度不敏感神经元的放电活动则无明显改变。以上结果表明弓状核内存在以冷敏神经元居多的温度敏感神经元,并探讨了丁香酚的降温作用与它能够抑制弓状核的冷敏神经元,激活热敏神经元的电活动有关,亦成为弓状核参与体温调节的有力佐证     

生石膏对致热原作用下猫PO／AH温敏神经元放电的影响

目的:研究中药生石膏解热作用的中枢机制.方法:复制发热模型后,静脉注射生石膏,应用微电极细胞外记录技术记录视前区-下丘脑前部(PO/AH) 温敏神经元单位放电的变化情况.结果:给予致热原后,PO/AH 区热敏神经元放电频率显著减少(P<0.01 ),冷敏神经元放电频率明显增加(P<0.05); 静脉注射生石膏后,可反转致热原对PO/AH区温敏神经元的上述作用,与给药前相比,热敏神经元放电频率明显回升(P<0.01 ),冷敏神经元放电频率明显回降(P<0.05).结论:提示生石膏是通过影响致热原作用下PO/AH区温敏神经元的放电活动,在中枢神经元水平上发挥解热作用的.     

胃动素对大鼠下丘脑胃牵张敏感神经元和胃运动的影响(英文)

目的:研究胃动素对下丘脑弓状核胃牵张敏感神经元放电活动和胃运动的影响。方法:采用4管玻璃微电极细胞外记录胃动素对大鼠弓状核胃牵张敏感神经元活动,采用胃内置传感器观察胃动素对对清醒大鼠胃运动的影响。结果:65.5%的弓状核神经元为胃扩张敏感性神经元,其中55.6%为胃扩张兴奋性神经元,44.4%为抑制性神经元。胃扩张刺激后兴奋性神经元的放电频率显著增加(P<0.01),而抑制性神经元的放电频率显著降低(P<0.01)。弓状核内微量注射胃动素,70%的兴奋性神经元在胃扩张刺激后表现为兴奋作用,17.5%的神经元表现为抑制作用,并且放电频率显著增加(P<0.05)。同样,在抑制性神经元中,65.6%在注射胃动素后引起电活动增强,放电频率显著降低(P<0.05)。而胃动素受体拮抗剂GM-109可以完全阻断这种由胃动素诱导的兴奋作用,提示,胃动素在弓状核通过其特异性受体调控神经元活动。在胃运动实验中,弓状核微量注射胃动素后,胃运动的收缩频率和幅度都显著增加(P<0.05);同时,这种兴奋作用也可被GM-109阻断。结论:研究证实了弓状核胃动素神经元接收来自胃感受器的外周躯体感觉传入神经的冲动,并通过某些下级核团通路发挥...     

兔孤束核腹外侧区微量注射谷氨酸钠及甘氨酸对弓状核诱发电位的影响

实验在６６只麻醉、制动,断双侧颈迷走神经和人工通气的家兔上进行。通过微量注射神经元胞体兴奋剂谷氨酸钠和神经元胞体抑制剂甘氨酸,改变孤束核腹外侧区神经元兴奋活动,探讨对下丘脑弓状核诱发电位的影响及其可能的机制和意义。实验结果如下：（１）孤束核腹外侧区微量注射谷氨酸钠,可使膈神经放电显著增加和使弓状核诱发电位Ｐ２及Ｎ２波幅显著降低;而微量注射甘氨酸则使膈神经放电显著减少和使弓状核诱发电位Ｐ２及Ｎ２波幅显著增大。（２）静脉注射纳洛酮对谷氨酸钠引起的膈神经放电兴奋效应无明显影响,但能翻转谷氨酸钠对弓状核诱发电位Ｐ２及Ｎ２波幅的抑制效应。提示：孤束核腹外侧区呼吸神经元的兴奋活动可扩散至弓状核,并对弓状核诱发电位产生影响,此影响可能是由内源性阿片系统参与而实现的。     

兔孤束核腹外侧区微量注射保氨酸钠及甘氨酸对弓状核诱发电位的影响

实验在６６只麻醉、制动,断双侧颈迷走神经和人工通气的家兔上进行。通过微量注射神经元胞体兴奋剂谷氨酸钠和神经元胞体抑制剂甘氨酸,改变孤束核腹外侧区神经元兴奋活动,探讨对下丘脑弓状核诱发电位的影响及其可能的机制和意义。实验结果如下：（１）孤束核腹外侧区微量注射谷氨酸钠,可使膈神经放电显著增加和使弓状核诱发电位Ｐ２及Ｎ２波幅显著降低;而微量注射甘氨酸则使膈神经放电显著减少和使弓状核诱发电位Ｐ２及Ｎ２波幅     

隔区和第Ⅲ脑室注射精氨酸加压素对家兔视前区—下丘脑前部温敏神经元放电的影响

为了研究精氨酸加压素（ＡＶＰ）的抗热机理,本研究观察了家兔隔区和第Ⅲ脑室微量注射ＡＶＰ对视前区一下丘脑前部（ＰＯ－ＡＮ）温度敏感神经元放电的影响。结果如下：（１）隔区注射ＡｖＰ能使ＰＯ－ＡＨ热敏神经元放电明显增加,冷敏神经元放电明显减少。（２）第Ⅲ脑室注射ＡＶＰ只能使部分ＰＯ－ＡＨ热敏神经元放电增加,冷敏神经元放电减少;而另外一部分热敏神经元和冷敏神经元则出现相反的效应。实验结果表明,隔区注射ＡＶＰ的抗热作用,可能是由于注射到隔区的ＡＶＰ使该区的神经元活动发生改变,而影响了ＰＯ—ＡＨ温度敏感神经元的活动所致。也提示隔区在体温调节中可能起重要作用。     

纳洛酮翻转刺激大鼠下丘脑弓状核对中缝背核单位活动的影响

实验在麻醉或制动的大鼠上进行。用玻璃微电极记录中缝背核单位活动及其对刺激弓状核的反应,并观察注射纳洛酮的作用。主要结果如下:(1)电刺激弓状核能明显影响中缝背核单位的放电活动,主要表现为抑制;(2)注射纳洛酮能翻转刺激弓状核对中缝背核单位放电的影响;(3)注射纳洛酮使中缝背核单位的自发放电频率显著增加。上述结果提示:刺激弓状核对中缝背核单位放电的影响,可能是通过释放内源性阿片样物质(β-内啡肽)而引起的。     

甲状腺素与甲巯咪唑对大鼠视前区与下丘脑前部温度敏感神经元的影响

本文观察了皮下注射甲状腺素和胃饲甲巯咪唑对大鼠视前区-下丘脑前部(PO/AH)温度敏感神经元的影响。PO/AH 存在温度敏感神经元(TSN)和温度不敏感神经元(TIN),在 TSN 中又可分为热敏神经元(WSN)和冷敏神经元(CSN)。在正常大鼠,TSN∶TIN=1.43∶1;WSN∶CSN=1.86∶1。以上比例可被甲状腺素和甲巯咪唑所改变:前者使之分别下降为1∶2.36和1.20∶1;后者使 TSN∶TIN 下降为1∶1.29,WSN∶CSN 上升为2.40∶1。各组神经元构成比有显著性差异,(X_2=9.64,P<0.05)。正常大鼠中所记录到的高频神经元(>15H_z)占32%(11/34),甲状腺素组仅有8%(3/37),甲巯咪唑组为9%(3/32)。实验中还发现甲状腺素组和甲巯咪唑组中 TSN 对热刺激的耐受性显著低于正常组。以上结果提示:甲状腺素或甲巯咪唑所致体温上升或下降可能与 PO/AH 神经元兴奋性及比例等改变有关;甲状腺素合成、释放和代谢的紊乱可以在下丘脑水平干扰体温调节过程;但这一作用的具体途径有待于进一步研究。     

去甲肾上腺素对猕猴额叶延缓辨别作业相关神经元活动的效应

为了研究去甲肾上腺素在大脑认知功能中的作用,在3只猕猴进行延缓辨别作业的同时,在额叶弓状沟上支内侧部的皮层区,记录了230个作业相关神经元的电活动。对其中159个神经元观察了微量电泳去甲肾上腺素、妥拉苏林或心得安的效应。这些神经元在作业各期的分布是:开始期11个,暗示期28个,延缓期66个,反应期54个。约2/3的神经元在作业中出现兴奋反应(放电增多),1/3为抑制反应(放电减少)。在延缓期出现抑制反应的神经元,绝大多数对去甲肾上腺素敏感。在电泳去甲肾上腺素时,神经元的自发放电减少,延缓期的抑制加深。电泳妥拉苏林或心得安则出现相反的效应,即自发放电增多,延缓期的抑制减弱或不出现抑制,并可拮抗电泳去甲肾上腺素的抑制效应。实验结果提示,在额叶弓状沟上支内侧皮层神经元的注意、短时记忆等认知功能中,可能有去甲肾上腺素参与作用,主要参与神经活动的抑制过程。     

针刺对同时在丘脑束旁核和尾核记录的痛兴奋与痛抑制神经元单位放电的影响

在44只大白鼠上,通过两根玻璃微电极同时引导丘脑束旁核和尾核神经元的放电,观察伤害性刺激作用于坐骨神经和电针“足三里”对两个神经元放电的影响。实验共记录到81对两个神经元的同时放电,其中包括26对痛兴奋、3对痛抑制、28对痛兴奋和痛抑制、24对其他组合类型的神经元放电。实验结果表明:1.从大白鼠尾核可同时记录到痛兴奋和痛抑制两种神经元的电活动,未见痛兴奋和痛抑制神经元的放电型式相互转换。2.同一伤害性刺激可同时引起丘脑束旁核和尾核中的两个痛兴奋神经元兴奋、两个痛抑制神经元抑制、或一个痛兴奋神经元兴奋和另一个痛抑制神经元的抑制。3.电针“足三里”可同时使丘脑束旁核和尾核的痛兴奋神经元兴奋减弱或痛抑制神经元抑制反应减弱(抑制解除)。本工作证明,伤害性刺激可同时影响丘脑束旁核和尾核中痛兴奋和痛抑制神经元的单位放电变化,而电针“足三里”又同时对两核团中痛兴奋和痛抑制神经元的活动具有调整作用。     

Race and Racism in America and in Anthropology

Race in North America: Origin and Evolution of a Worldview . Audrey Smedley
Anthropology and Race . Eugenia Shanklin     

Degradation and conversion of somatostatin in normal and diabetic rats in vivo and in vitro

Plasma somatostatin-like immunoreactivity in the portal and jugular veins of streptozotocin diabetic rats was compared with that in normal control rats. In the diabetic group, somatostatin levels in the portal (p less than 0.05) and jugular (p less than 0.01) veins were both elevated compared with those in the control group. Moreover, the degree of elevation was greater in the jugular vein than in the portal vein. To further investigate the role of the liver in the clearance of somatostatin-28 in vivo, 2 micrograms of somatostatin-28 was administered as a bolus into the external jugular vein of intact and functionally hepatectomized rats. The mean half-time of somatostatin-28 was significantly longer in intact diabetic rats than in controls (p less than 0.05). The functional hepatectomy did not cause a significant difference in the half-time in diabetic rats but made it longer in control rats. These results suggest that the longer half-time of somatostatin-28 in diabetic rats in vivo is due to its slower hepatic clearance. The hepatic clearance of somatostatin-28 and somatostatin-14 was further studied in vitro using a recirculating liver perfusion method. The hepatic clearance of 1.2 nM of either somatostatin-28 or somatostatin-14 was significantly lower in diabetic rats than in controls (p less than 0.01). This indicates that elevated plasma somatostatin levels in diabetic rats are caused at least in part by decreased hepatic clearance of somatostatin.(ABSTRACT TRUNCATED AT 250 WORDS)     

Obestatin and ghrelin in obese and in pregnant women

We identified, through qPCR, receptor mRNA for a number of gut peptides in female human omental fat: the incretins, GIP and GLP-1, the orexigenic peptides PYY-Y1 and -Y2 and ghrelin, and the anorexigenic peptide obestatin. Four cohorts of women were examined: lean controls (BMI<23), obese (BMI>41), obese diabetic and term pregnant women. Human fat expressed receptor mRNAs for all six peptides. Pregnant women expressed roughly three times as much orphan GPR-39 receptor, a proposed obestatin receptor, than other women and less than half as much of the ghrelin receptor (GHSR-1a). An immunoblot probed with a GPR-39 selective antibody yielded a single band corresponding to the correct molecular weight (52 kDa) for the proposed obestatin receptor. Fluorescent immunohistochemistry of human fat employing the same antibody indicated the receptor protein was localized to the adipocyte cell membrane. The concentration of obestatin circulating in blood was measured in the same cohort of women and was significantly lower in obese and obese diabetic women compared to control.     

Deoxynivalenol and nivalenol in wheat and by-products in Argentina

The deoxynivalenol and nivalenol contamination in wheat and by-products obtained through milling was analized by Trucksess method slightly modified in the proportion of acetonitrile—water (3:1). Only one sample of wheat showed deoxynivalenol contamination, 1,200μg/kg. No samples obtained in different stages of the milling were contaminated with deoxynivalenol or nivalenol. In the commercial wheat flours the levels found ranged between 400 and 800μg/kg, as follows: 400μ/kg, 5 samples; 800jug/kg, 1 sample.     

Update in research and methods in proteomics and bioinformatics

The 3rd International Conference on Proteomics & Bioinformatics (Proteomics 2013)

Philadelphia, PA, USA, 15–17 July 2013

The Third International Conference on Proteomics & Bioinformatics (Proteomics 2013) was sponsored by the OMICS group and was organized in order to strengthen the future of proteomics science by bringing together professionals, researchers and scholars from leading universities across the globe. The main topics of this conference included the integration of novel platforms in data analysis, the use of a systems biology approach, different novel mass spectrometry platforms and biomarker discovery methods. The conference was divided into proteomic methods and research interests. Among these two categories, interactions between methods in proteomics and bioinformatics, as well as other research methodologies, were discussed. Exceptional topics from the keynote forum, oral presentations and the poster session have been highlighted. The topics range from new techniques for analyzing proteomics data, to new models designed to help better understand genetic variations to the differences in the salivary proteomes of HIV-infected patients.