蓝斑核和中缝背核参与电刺激弓状核引起的大鼠胃内压降低的反应

选用 Wistar 大鼠80只。在乌拉坦麻醉下观察了电刺激弓状核对胃内压的影响并初步分析了其作用的中枢途径。结果为:(1)刺激时,胃内压显著降低;(2)分别电解损毁双侧蓝斑核和中缝背核,均可减弱弓状核的这一作用;(3)侧脑室注射纳洛酮不影响弓状核的这一作用。上述结果表明,电刺激弓状核降低胃内压的作用需有蓝斑核和中缝背核参与,而弓状核内富含的β-内啡肽能神经元可能与这一作用无关。     

中缝背核参与下丘脑弓状核对丘脑束旁核痛单位放电的抑制

电解损毁中缝背核(DR)、DR 区微量注射纳洛酮或 β-内啡肽抗血清都能明显翻转电刺激大鼠下丘脑弓状核(ARC)对丘脑束旁核(PF)单位痛诱发放电的抑制;而电解损毁中缝大核(NRM)、NRM 区微量注射纳洛酮、β-内啡肽抗血清,或 DR 区微量注射生理盐水、正常兔血清对刺激 ARC 的这种抑制效应均无明显影响。本实验结合以往实验结果提示;从 ARC 到PF 可能存在着这样一条痛觉调制通路,即通过 ARC 的β-内啡肽能纤维影响 DR 单位的活动,继而又通过 DR 的5-羟色胺能纤维影响 PF 单位的活动,从而影响痛觉的感知。     

刺激中缝背核和蓝斑对下丘脑弓状核区诱发电位的影响

实验在用水合氯醛麻醉的雄性成年大鼠上完成。目的是观察刺激中缝背核和蓝斑对刺激坐骨神经诱发下丘脑弓状核区电位的影响。结果表明:(1)电刺激中缝背核和蓝斑与腹腔注射吗啡一样,可以明显抑制外周伤害性刺激所诱发的弓状核区电位的第三个迟发成分(Sw_3);(2)脑室注射及微电泳作为中缝背核和蓝斑各自所释放的主要神经递质——5-羟色胺和去甲肾上腺素也能明显地抑制 SW_3成分。     

刺激大鼠伏核和伏核内微量注射纳洛酮对外侧缰核“痛”单位放电的影响

在清醒、肌肉麻痹状态下的大鼠,观察到重复电刺激伏核对外侧缰核痛兴奋单位(LHPE)自发放电和痛诱发放电有明显的抑制作用。腹腔注射纳洛酮(6mg/kg体重)可阻断这种抑制作用。而电刺激伏核对外侧缰核痛抑制单位放电有兴奋作用。双侧伏核内微量注射纳洛酮(1.8ug,4min注完)使 LHPE 放电增加,注射吗啡(15ug,4min注完)可抑制 LHPE 放电。本文就以上结果在针刺镇痛中的意义进行了讨论。     

刺激下丘脑弓状核对丘脑束旁核单位痛诱发放电的影响和初步分析

1.电刺激大鼠下丘脑弓状核(ARC)对外周伤害性刺激引起的丘脑束旁核(PF)单位的痛诱发放电有明显的抑制作用,这种抑制作用可被纳洛酮所翻转。2.切断脊髓背半部后,刺激ARC对PF单位痛诱发放电的抑制作用依然存在。3.腹腔注射对氯苯丙氨酸(色氨酸羟化酶抑制剂)后,刺激ARC 的抑制作用消失。4.从ARC到PF存在着一条有内源性阿片样物质(可能是β-内啡肽)和5-羟色胺参与的上行痛觉调制通路。     

在清醒家兔中电针对刺激下丘脑引起的防御反应的抑制作用

在清醒家兔中电刺激下丘脑背内侧区可引起血压升高、肾交感神经放电增加、心率减慢等一系列防御反应的表现。用低频电脉冲刺激一侧“足三里”穴20min,可明显抑制刺激下丘脑引起的防御反应。这种抑制效应在停止电针后仍能持续一段时间,但可被静脉内注射纳洛酮(0.4mg/kg)翻转。预先注射纳洛酮也能防止电针的抑制效应。损毁下丘脑基底部包括弓状核在内的局部区域后,电针对防御反应的抑制作用基本消失。在弓状核区微量注射 L-谷氨酸钠(50mM,1μl)也可抑制刺激下丘脑引起的防御反应。这种抑制效应同样可被静脉内注射纳洛酮翻转。以上实验结果表明,电针可抑制刺激下丘脑引起的防御反应,弓状核区的内啡肽神经元可能在电针对防御反应的抑制效应中起重要的作用。     

刺激中缝背核对视交叉上核光敏神经元单位放电的影响

本实验观察刺激中缝背核对大鼠视交叉上核光敏神经元单位放电的影响,并进行药理学分析。结果表明,刺激ＤＲ能明显抑制ＳＣＮ神经元光诱发放电,这种抑制作用能被单胺氧化酶抑制剂优降宁增强,能被５－ＨＴ合成抑制剂对氯苯丙氨酸减弱,还能被５－ＨＴ受体拮抗剂赛庚啶阻断。结果提示,５－ＨＴ参与了刺激ＤＲ对ＳＣＮ光敏神经元放电的抑制。     

唇针及麦角酰二乙胺(LSD)对大鼠中缝背核单位放电的影响

本实验在麻醉或固定的大鼠上进行。电刺激坐骨神经和用有齿镊夹尾作为伤害性刺激。电针“人中”和“承浆”穴位。用玻璃微电极细胞外记录中缝背核神经元的单位放电。其主要结果如下:1.外周伤害性刺激能使大鼠中缝背核大多数神经元的自发放电频率减慢或暂时停止。2.唇针可激活中缝背核大多数神经元,使其自发放电频率增加和使大多数中缝背核神经元对伤害性刺激反应的持续时间缩短。3.LSD 对中缝背核神经元自发放电的抑制作用与其剂量大小密切相关。     

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...     

刺激大鼠下丘脑背内侧核对丘脑束旁核痛相关神经元放电的影响

本文在 79只清醒麻痹大鼠身上,用玻璃微电极记录丘脑束旁核痛兴奋(PfPE)和痛抑制(PfPI)单位的放电及其对刺激下丘脑背内侧核(DMH)的反应,并观察切割脊髓背外侧束的效应。主要结果如下:(1)刺激DMH使PfPE 单位的自发放电及痛放电有明显的抑制作用,而使PfPI 单位的自发放电增多,并解除伤害性刺激引起的抑制效应;(2)刺激DMH引起PfPE 单位的抑制效应,在切割脊髓背外侧束后仍然出现。上述结果提示:DMH 对丘脑束旁核在处理痛觉信息上具有调制作用,这种调制作用可能不通过脑干下行性抑制系统完成,而主要是通过脊髓上联系抑制丘脑束旁核神经元对痛传入的反应。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.