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在清醒家兔中,双侧损毁导水管周围灰质(PAG)的腹侧部或在双侧PAG腹侧部微量注射阿片受体拮抗剂纳洛酮,可明显阻断电针对刺激下丘脑背内侧区引起的防御反应的抑制效应。双侧损毁PAG腹侧部或在双侧PAG腹侧部微量注射纳洛酮,也都能减低直接兴奋弓状核区对防御反应的抑制作用的程度,在PAG 腹侧部微量注射阿片受体激动剂吗啡则可抑制刺激下丘脑引起的防御反应。以上实验结果提示,PAG 腹侧部的阿片受体可能参与电针抑制防御反应的机制。本文讨论了电针可能激活弓状核的内啡肽神经元并激活PAG 腹侧部的阿片受体而对防御反应发生抑制作用的可能性。 相似文献
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兔下丘脑弓状核区在躯体传入冲动抑制刺激下丘脑诱发的期前收缩中的作用 总被引:1,自引:0,他引:1
实验在62只乌拉坦、氯醛醣麻醉兔上进行,用三碘季铵酚制动,由人工呼吸机维持通气。电解损毁下丘脑弓状核区或者在该区微量注射纳洛酮(2μg/1μl)可消除刺激腓深神经对刺激下丘脑诱发的期前收缩的抑制作用。在下丘脑弓状核区微量注射吗啡(2μg/1μl)可减少刺激下丘脑诱发的期前收缩次数,而注射纳洛酮(2μg/1μl)则使期前收缩数增多。无论损毁延髓中线区或在中央灰质内微量注射纳洛酮(2μg/1μl),均可消除下丘脑弓状核区微量注射吗啡(2μg/1μl)对刺激下丘脑诱发的期前收缩的抑制作用。因而,在下丘脑弓状核区微量注射吗啡,可能经中脑中央灰质而发挥对刺激下丘脑诱发的期前收缩的抑制作用。 相似文献
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损毁伏核可明显削弱电刺激腓深神经(DPN)对兴奋下丘脑背内侧核诱发的升压反应和心肌缺血的抑制作用(P<0.05,P<0.01)。电刺激伏核可引起明显的降压效应。中脑中央灰质腹侧部(vPAG)微量注射纳洛酮可明显衰减伏核的减压效应;损毁vPAG甚至可翻转伏核的减压效应,引起轻度升压(P<0.01)。损毁弓状核后伏核的减压效应基本消失,弓状核内微量注射纳洛酮明显衰减伏的的减压效应。故DPN传入冲动可能 相似文献
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本实验以电刺激鼠尾-嘶叫法和甲醛爪内注射-行为法两种测痛方法观察到:(1)大鼠下丘脑弓状核区微量注射神经元胞体兴奋剂谷氨酸单钠(MSG)300μg/1μl 可引起明显镇痛效应。(2)双侧蓝斑内微量注射 β-内啡肽抗血清各0.1μl 可明显对抗 MSG 兴奋弓状核区神经元的镇痛效应。(3)直接在双侧蓝斑内微量注射 β-内啡肽各1ug/0.25μl 也可产生明显的镇痛效应。上述结果表明:下丘脑弓状核区注射 MSG 兴奋其中的 β-内啡肽能神经元群,可能通过下行纤维末梢释放 β-内啡肽,影响蓝斑神经元的活动,从而产生镇痛效应。 相似文献
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下丘脑室旁核加压素能神经元参与电针刺激对实验性内脏痛的抑制 总被引:1,自引:0,他引:1
本实验采用内脏痛的实验模型,探讨室旁核中的加压素在针刺抑制内脏痛中的作用。实验结果如下:(1)大鼠在在射酒石酸锑钾(0.1%,10ml/kg,i.p.)后,出现可定量的扭体反应,能作为观察内脏痛的客观指标。(2)电针对内脏痛有抑制效应,即具有镇痛作用。(3)电刺激室旁核,能加强电针对内脏痛的抑制效应,损毁室旁核,则此抑制效应基本消失。(4)脑室注射加压素抗血清(14μl)或加压素拮抗剂[d(CH_2)_5Tyr(Me)-AVP,500ng/5μl]都能明显减弱电针的抑制效应。(5)腹腔注射加压素拮抗剂(10μg/kg),不能翻转电针的抑制效应。上述实验结果表明,下丘脑室旁核的加压素能神经元参与了电针刺激对实验性内脏痛的抑制。 相似文献
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大鼠下丘脑弓状核区在唇针镇痛中的作用 总被引:2,自引:0,他引:2
下丘脑弓状核区和脑内参与痛觉调制的结构有复杂的纤维联系,脑内β-脂肪激素-β-内啡肽-ACTH 神经元系统的胞体亦主要集中于下丘脑弓状核区。本实验用电解损毁、H 刀游离和电刺激大白鼠弓状核区的方法,研究该区在痛觉调制和唇针镇痛中的作用。(1)电解损毁或 H 刀游离弓状核区后基础痛阈未见明显改变,但唇针镇痛效应均明显降低。(2)单纯电刺激弓状核区能明显升高基础痛阈;唇针和电刺激弓状核区同时进行时的镇痛效应比单纯唇针时的镇痛效应有明显提高。根据这些结果,讨论了下丘脑弓状核区在大白鼠唇针镇痛中的作用。 相似文献
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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 总被引:3,自引:1,他引:2
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。 相似文献
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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. 相似文献
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正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases 相似文献
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Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme
responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare
the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show
that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by
distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of
demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least
one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of
the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable
potent antiproliferative synthetic drugs. 相似文献
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RICHARD E. NORRIS 《Botanical journal of the Linnean Society. Linnean Society of London》1991,106(1):1-40
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. 相似文献
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JOAN VALUÈS MONTSERRAT TORRELL NÚRIA GARCIA JACAS 《Botanical journal of the Linnean Society. Linnean Society of London》2001,137(4):399-407
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. 相似文献