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1.
SNP抑制5-HT诱导的胞内游离钙浓度升高和内钙释放 总被引:2,自引:0,他引:2
用Fura - 2/AM 荧光测量技术研究了5 - 羟色胺(5- HT) 诱导的大鼠尾动脉平滑肌细胞胞内钙升高和一氧化氮(NO) 的抑制效应。实验表明, 胞外0m mol/ L Ca2 + 时胞内静息[Ca2 + ] i 为20 .2±8 .6nmol/L(n = 8) 。10μmol/L 5- HT 可诱导出胞内钙库释放引起的瞬态[Ca2 +]i 升高,其峰值达245 .7 ±71.6nmol/ L(n = 6) 。10 - 7 mol/L 硝普钠(SNP) 可抑制5- HT 诱导的[Ca2 +]i 升高,其峰值浓度降为75.1±35 .9nmol/L(n = 5) 。当细胞浴液含2.5m mol/L Ca2 + 时,静息[Ca2 +]i为112 .8 ±10 .3nmol/ L(n = 5) , 这时10μmol/ L 5 - HT 可诱导[Ca2 + ] i 的峰值为252 .3 ±80 .6nmol/L(n = 4) ,以及其后平台浓度为143 .0 ±37 .6nmol/L(n = 4) ,略大于[Ca2 +]i 为112.8 ±10 .3nmol/L 的静息浓度,为外钙内流引起。10 - 7 mol/L SNP 也可抑制5- HT 诱导[Ca2 + ]i 平台相浓度。平台浓度由143 ±47 相似文献
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P物质对大鼠DRG神经元胞体膜的作用 总被引:17,自引:1,他引:17
本文在大鼠DRG神经元标本上应用细胞内记录,以确定SP对DRG细胞的膜反应及其可能的离子机制。实验所测DRG细胞静息膜电位为-58.9±8.2mV(X±SE,n=81)。传导速度:A_(α/β)细胞为20.4±4.8m/s(X±SE),范围14.1-28.7m/s(47/60);Aδ及C类细胞为9.8±5.2m/s,范围1.2-13.7m/s(13/60)。浴槽滴加SP(10 ̄(-7)-3×10 ̄(-4)mol/L)在大多数细胞可引起明显的膜去极化反应(56/60)。少数细胞对SP无反应(4/60)。在SP去极化期间膜电导值有所增加,从平均值2.72×10 ̄(-8)mho增加24.6%(n=3)。所测逆转电位值在+40-+50mV之间(n=3)。浊流平衡液(BSS)中NaCl以氯化胆碱置代,或用含TTX(10 ̄(-5)mol/L)的BSS灌流,可使SP-去极化幅值大大减小但不能完全消除。而高(20mmol/L)和低(0mmol/L)Ca ̄(2+)的BSS灌流时,使SP-去极化幅值相应的增加和降低。用含10 ̄(-4)mol/LCd ̄(2+)及10 ̄(-2)mol/LTEA的BSS灌流,均使SP-去极化明显减小。 相似文献
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本研究着重探讨表皮生长因子(EGF)对大鼠肺动脉的收缩作用及对肺动脉平滑肌细胞分裂增殖的影响。浓度为1×10-9-1×10-7mol/L的EGF可引起大鼠肺动脉剂量依赖性收缩(r=0.968,P<0,001),其Emax为100.6mg,EC50为11.96nmol/L。在同时存在0.5%胎牛血清(FCS)时,EGF能促进平滑肌细胞的3H-TdR参入率,该作用与剂量呈正相关(r=0.823,P<0.05),其EC50为6.5×1O-12mol/L。1×10-9mol/L的EGF+0.5%FCS能产生与10%FCS相当的促细胞分裂增殖能力(在培养的第1,3,5,7天,二者促分裂增殖能力相差不明显,P均>0.05,第9天时,前者大于后者,P<0.05)。1×10-9mol/LEGF单独存在时对平滑肌细胞未显示出明显的致分裂活性。上述作用提示ECF在某些肺血管病变如缺氧性肺动脉高压中可能有一定意义。 相似文献
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本实验采用堤式颅窗软脑膜微循环实验方法,利用去甲肾上腺素和α,β-受体阻断剂,研究了交感神经在缺氧性脑血管扩张反应(HCV)中的作用。去甲肾上腺素(10-7mol/L和10-6mol/L)对软脑膜微动脉无明显作用。β-受体阻断剂普萘洛尔(局部用药,下同)对HCV无明显影响,而用10-6mol/L哌唑嗪阻断软脑膜微动脉α-受体可明显增强HCV(由21.5±9.8%增至30.6±9.2%,P<0.01)。结果提示,正常情况下交感神经对脑血管影响较小,但在缺氧时,交感神经对脑血管有收缩作用。交感神经可能通过增加其末梢释放去甲肾上腺素,作用于α-受体,限制微劝脉扩张而在缺氧性脑血管扩张反应中起调节作用。 相似文献
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α受体激动对绵羊心肌瞬时性内向离子流的影响 总被引:1,自引:0,他引:1
用乙酰毒毛旋花子甙元(AS)0.05μmol/L诱发绵羊心浦肯野纤维产生稳定的瞬时性内向离子流(Iti),用普萘洛尔0.5μmol/L阻断β受体,观察α受体激动剂苯肾上腺素(PE)0.3,1.0μmol/L对Iti幅值与时程的影响。PE1.0μmol/L灌流20,50min时Iti幅值分别由对照值12.8±1.9nA减小至10.7±1.2nA(n=5,P<0.05)与9.6±1.9nA(n=5,P<0.01);ItiD50时程分别由对照值145±24.4ms延长至183.3±28.1ms(n=5,P<0.05)与207.5±34.2ms(n=5,P<0.01),PE对Iti的抑制作用呈剂量依赖性与时间依赖性。Iti到达峰值的时间和回复到基线的时间都延长,提示PE作用下Iti通道动力学发生了变化。如果在β受体激动剂异丙肾上腺素(ISO)1.0μmol/L增强Iti的基础上,PE1.0μmol/L灌流10min,对Iti幅值的抑制及时程的延长作用更显著,Iti幅值由对照值15.6±3.2nA减小到10.3±2.2nA;ItiD50由92.5±14.3ms延长到132.5±36.0ms(n=5,P<0.01)。 相似文献
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在家兔离体肺内动脉、脑基底动脉环观察了过氧化氢(H2O2)及次黄嘌呤+黄嘌呤氧化酶(HX+XO)对动脉环缺氧反应的影响。结果发现:(1)H2O21×10-5mol/L加强f去内皮肺动脉环(PA-)的缺氧收缩幅度(TIH),而H2O23×10-5mol/L、HX10-4mol/L+XO0.1及0.03U/ml则可抑制内皮完整肺动脉环(PA+)及PA-的TIH(P<0.05);(2)各剂量H2O2及HX+XO对有、无内皮的脑基底动脉环的TIH均无显著影响。 相似文献
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丹皮酚对心肌细胞自律性和延迟后除极的影响 总被引:8,自引:0,他引:8
目的与方法:采用常规玻璃微电极技术研究丹皮酚对离体心肌细胞自律性(AM)、延迟后除极(DAD) 及触发活动(TA)的影响。结果:1.8×10-4mol/L丹皮酚灌流组,肾上腺素(Adr)的阈浓度空白对照组为(1.28±0.57)μmol/L,药后为(1.56±0.53)μmol/L(n=9,P>0.05);用(1.8×10- 3) mol/L丹皮酚(Pae)灌流组,Adr 浓度由空白对照组的(1.22 ±0.62)μmol/L升高到(6.22±2.11)μmol/L(n=9,P<0.01)。1.8×10-3mol/L的Pae 能明显抑制哇巴因(Oua)诱发的DAD的幅值,当基本刺激周长为500,400,300 和200 ms 时,其DAD幅值从(5.5±2.0)mV,(7.3±2.1)mV,(8.0 ±2.4)mV和(9.2±1.9)mV减小到(3.0±1.1)mV、(3.6±1.7)mV,(4.3±2.0) mV和(5.9 ±1.6) mV,P<0.01。当基本刺激周长为200 ms时,TA 数目由5.5±1.0 降至0.7±0.3(P<0.01)。结论:丹皮酚能抑制心肌细胞AM、DAD及TA,具有抗心律失常作用 相似文献
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牛磺酸调节缺氧性肺、脑血管反应的机理研究 总被引:9,自引:0,他引:9
本实验从磷脂酶A_2(PLA_2)、前列腺素(PGs)、白三烯(LTs)和过氧化脂质(LPO)方面探讨了牛磺酸调节肺、脑血管对急、慢性缺氧反应的机制。急性缺氧时狗出肺与出脑血中LPO增加,PLA,活性有升高趋势,但出脑与出肺(入脑)血相比无显著性差异。出肺与出脑血中LTC_4、TXB_2、6-Keto-PGF_(1a)及TXB_2/6-Keto-PGF_(1a)比值均升高。慢性缺氧大鼠肺、脑组织中PLA_2活性均升高。牛磺酸增加缺氧时6-Keto-PGF_(1a),减弱其它变化。提示牛磺酸对缺氧性肺缩血管反应的调节作用可能与降低缺氧时PLA_2活性,抑制脂质过氧化和LTC_4、TXA_2生成,降低TXA_2/PGI_2比值有关;而牛磺酸减弱缺氧性脑舒血管反应不是直接通过上述变化起作用的。 相似文献
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蚯蚓体内一种纤溶酶原激活剂(e-PA)对ATEE的降解 总被引:3,自引:0,他引:3
赤子爱胜蚓(Eiseniafetida)体内的一种纤溶酶原激活剂(e-PA)能够降解人工合成底物N-乙酰-L-酪氨酸乙酯(ATEE),该降解反应的最适pH为8.5,而且在0.2mol/LNa2HPO4中的活性要强于在0.05mol/LTris-HCl(pH8.5)中.分别测定了e-PA的大小亚基及全酶在0.2mol/LNa2HPO4与0.05mol/LTris-HCl(pH8.5)两种体系中的Km和Kcat.结果表明,在0.2mol/LNa2HPO4中,全酶的ATEE活性远远高于大小亚基单独的ATEE活性,而在0.05mol/LTris-HCl(pH8.5)中则没有这种现象.从蛋白质结构的角度对这一结果作了解释.用不同抑制剂和e-PA作用,结果表明,pepstatin,E-64和EDTA对e-PA的ATEE活性都有不同程度的抑制,这一点与e-PA的BAEE活性不同. 相似文献
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EDRF对PE引起的大鼠主动脉缩血管效应的作用 总被引:1,自引:0,他引:1
本文研究EDRF(endothelium-derivedrelaxingfactor,EDRF)对PE(phenylephrine)引起的大鼠主动脉收缩反应的影响。内皮完整和去内皮的大鼠主动脉环悬挂于器官浴槽中,测定血管的张力和收缩速度的变化。所有的实验在消炎痛(indomethacin,10μmol/L)存在下进行。用美兰(methyleneblue,MB,10μmol/L)或左旋硝基精氨酸(NG-nitro-L-arginine,L-NNA,30μmol/L)处理内皮完整的大鼠主动脉环,PE的剂量-收缩张力曲线明显左移,EC30值均降低5倍,最大反应比率分别为1.6±0.4和1.6±0.5。在去内皮的大鼠主动脉环中,经MB和L-NNA处理后,仍可见EC30下降3倍,最大反应比率均为1.0±0.2。后者可能与血管平滑肌产生少量EDRF有关。我们的结果提示PE对血管的收缩反应也受血管内皮和平滑肌产生的EDRF的调控 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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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
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肝癌中HBV和HCV基因和抗原的分布及意义 总被引:1,自引:0,他引:1
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 相似文献
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H.-R. GREGORIUS 《Biological journal of the Linnean Society. Linnean Society of London》1984,23(2-3):157-165
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. 相似文献
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. 相似文献