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1.
采用单细胞电生理记录技术,对螽斯Gampocleis gratiosa听觉双轴突中间神经元TN2的声反应放电活动的基本特征进行了观测,发现TN2的放电模式为“phasic”型,最敏感频率为13kHz,反应阈值为31dB SPL,是一个高灵敏、宽带通的神经元。还研究了抑制性神经递质GABA及其拮抗剂苦毒素对TN2声反应的影响,发现GABA能抑制TN2的放电活动,而苦毒素则将其放电模式改变为“toni  相似文献   

2.
谷瑞民  孙明智 《生理学报》1997,49(3):321-326
在53只成年Wistar大鼠上,用玻璃微电极引导神经元放电,观察了尾核内注射γ-氨基丁酸后,尾核痛反应经元放电的变化和印防己毒素对GABA作用的阻断效应。尾核内每2分钟分别注射GABA25,50,100μg/2μl,尾核痛兴奋神经元诱发放电频率减少,潜伏期延长;痛抑制神经元放诱发放电频率减少,潜伏期延长;痛抑制神经元放电抑制时程缩短,放电频率增加。PEN和PIN电活动反应与GABA剂量间呈量效关系  相似文献   

3.
X. C. ZHANG 《植物研究》1998,18(1):107-117
GENUSANTROPHYUMKAULF.FROMCHINAANDNEIGHBORINGREGIONSX.C.ZHANG(Theherbarium(PE),InstituteofBotany,ChineseAcademyofSciences,Bei...  相似文献   

4.
刺槐宽叶和四倍体无性系的组织培养   总被引:13,自引:0,他引:13  
1植物名称刺槐(Robiniapseudoacacia)优良无性系:Tetraploidlocust、Glgastypelocust。2材料类别带腋芽的茎段。3培养条件(1)启动培养基:MS+6-BA0.25mg·L-1(单位下同)+NAA0.05。(2)分化培养基和继代培养基:MS+6-BA0.5+NAA0.1+AgNO310,MS+6BA0.5+NAA0.1。上述培养基均添加3%蔗糖、0.6%琼脂。(3)生根培养基:1/2MS+IBA0.2+NAA0.2,添加2%蔗糖0.6%琼脂。培养基pH…  相似文献   

5.
类别文献(篇数)专利(件数)AGENETICENGINEERINGANDFERMENTATIONA1NucleicAcidTechnology20574151A2Fermentation1326498BENGINEERINGB1BiochemicalEngineering432131CANALYSISC1SensorsandAnalysis11293DPHARMACEUTICALSD1....  相似文献   

6.
No 1AStudyoftheSkeletonsofZhouandHanDynastiesUnearthedintheMiddleandtheSouthRegionsofShandongProvinceSHANGHong ,HANKang xin ,WANGShou gong (1 )……AnInvestigationontheIncidenceoftheSupraorbitalForamenandtheHypoglossalCanalBridginginChineseAncientBoneanditsBe…  相似文献   

7.
通过对重组质粒pGXN300中的 2.3kb EcoRI片段测序分析发现,其上有一完整的lrp基因和部分 putA基因,与 King ND等[1]报道的 B.japonicum的lrp基因DNA序列有 88%同源性。利用 Tn5 gusA5定位 诱变方法,对质粒pGXN300进行插入诱变,得到2.3kb EcoRI片段上有Tn5gusA5插入位点的质粒pGXN300- T38,将pGXN300-T38转移到大豆馒生根瘤苗(B.japonicum)GX201中,得到的GX201转移接合子与不相容 质粒pPH1JI发生同源双交换。通过抗性及gusA活性检测,筛选到一lrp基因突变株。Southem杂交分析证 明这突变株的 Tn5 gusA5插入确实是同源交换而不是转座产生,表明 Tn5 gusA5 诱变可以应用于大豆慢生根 瘤菌中的突变林筛选。  相似文献   

8.
c—erbB2对大鼠黄体细胞hCG诱导的孕酮分泌的影响   总被引:6,自引:1,他引:5  
采用离体细胞体外孵育法,研究反义c-erbB2寡脱氧核苷酸(antisense c-erbB2 ODN)对大鼠黄体细胞hCG诱导的孕酮分泌的影响,及其与外源性cAMP和Ca^2+以及蛋白抑制剂放线菌酮(CYX)之间的关系。结果表明,反义c-erbB2以剂量相关方式抑制黄体细胞hCG诱导的孕酮的产生,同时使c-erbB2蛋白染色阳性的黄体细胞百分数下降,无义tat ODN没有相应的作用。10^-4  相似文献   

9.
在长江沙洲上搁浅的中华白海豚   总被引:5,自引:0,他引:5  
在长江沙洲上搁浅的中华白海豚STRANDINGOFANINDO┐PACIFICHUMP┐BACKEDDOLP┐HINONASANDBANKINTHEYANGTZERIVER中华白海豚(Sousachinensis,Osbeck)分布在西太平洋和印度...  相似文献   

10.
ANewTechniqueofMicroproteinelectrophoresisandUltrasensitiveStaining1PANGGuangchang2,ZHAODongxu3,YANGXinlinCHENGuangwen...  相似文献   

11.
本实验室曾经报道静脉注射安定对于清醒、麻痹、人工呼吸的家兔具有减低膈神经放电幅度、加快呼吸频率,缩短吸气时程(T_I)和呼气时程(T_E),降低动脉血压等作用。本工作在35只家兔中进一步分析了某些药物对安定的这些作用的影响。GABA 降低膈神经放电幅度和动脉血压,这与安定的作用相同,但 GABA 延长T_I、T_E和减慢呼吸频率,与安定的作用相反。事先用氨基酸脱羧酶抑制剂异烟肼处理,或用 GABA 受体拮抗剂印防己毒素处理,可阻遏安定减低膈神经放电幅度的作用。在事先用印防己毒素处理的家兔中,可见安定缩短 T_IT_E的作用不受影响。异烟肼或印防己毒素还能部分对抗安定的降压效应。阿片受体拮抗剂纳洛酮和5-HT 受体拮抗剂赛庚啶都不能阻遏安定降低膈神经放电幅度和动脉血压的作用。上述结果提示安定降低膈神经放电幅度的作用可能通过 GABA 这一中间环节,而内啡肽和5-HT可能不起重要作用。安定的降压作用需要有内源性 GABA 参与才得以持续较长时间,在减少GABA 或阻断 GABA 受体后,安定只有短暂的降压作用。  相似文献   

12.
微电泳GABA和5-HT对大鼠丘脑束旁核单位痛放电的影响   总被引:3,自引:1,他引:2  
本实验用多管微电极细胞外记录和离子微电泳方法,在水含氯醛麻醉的SD大鼠上观察了γ-氨基丁酸(GABA)和5-羟色胺(5-HT)以及它们的受体阻断剂(印防已毒素和赛庚啶)对丘脑束旁核(Pf)单位痛放电的影响。结果表明:(1)电泳GABA可抑制Pf神经元的痛放电,这作用可被电泳印防已毒素所阻断,而单独电泳印防己毒素可加强Pf的痛放电。(2)电泳5-HT对Pf单位痛放电在有些单位表现加强作用,另一些单位表现抑制作用,仅前者可被电泳赛庚啶所阻断。上述结果提示:在Pf神经元的痛放电活动中,GABA可能起抑制性作用,而5-HT可能通过不同的受体亚型既发挥其兴奋作用,也可有抑制作用。  相似文献   

13.
The effects of acetylcholine (ACh), carbamylcholine and gamma-aminobutyric acid (GABA) on the spike activity of uropod motoneurons were investigated electrophysiologically in the crayfish Procambarus clarkii Girard and Cambaroides japonicus de Haan. High concentrations of ACh were required to bring about an increase in the spike discharge of uropod motoneurons while carbamylcholine, which is not destroyed by cholinesterase, caused a marked increase in the motoneuron spike discharge even in low concentrations. Application of GABA in concentrations of 10(-5)-10(-2) M caused the decrease in the spike discharge of uropod motoneurons. Under the condition that the synaptic transmission onto uropod motoneurons was blocked by perfusing EGTA containing Ca2+-free saline with high-Mg2+, ACh increased the spike discharge of uropod motoneurons whereas GABA decreased it. The results suggested that ACh and GABA function as excitatory and inhibitory transmitters, respectively, in the crayfish central nervous system.  相似文献   

14.
Abstract— The effects of γ-butyrolactone (GBL) and picrotoxin on both the post-mortem and amino-oxyacetic acid (AOAA) induced accumulations of γ-aminobutyric acid (GABA) were examined in rats. GBL produced a marked dose-dependent decrease in AOAA-induced GABA accumulation in caudate. globus pallidus, cerebellar and cerebral cortices. The cingulate cortex showed the greatest response to GBL treatment; subanesthetic doses completely blocked the effect of AOAA. Picrotoxin increased the AOAA-induced accumulation of GABA in parietal, entorhinal and cerebellar cortices, and had no significant effect in pyriform or cingulate cortices. Neither drug significantly altered the post-mortem accumulation of GABA. Results suggest that picrotoxin, a GABA antagonist and convulsant drug, causes an increase in GABA synthesis in vivo. The apparent decrease in GABA synthesis following GBL treatment was greater than that observed with anesthetic doses of chloral hydrate and was not blocked by picrotoxin. Alterations in the activity of GABA neurons, cerebral glucose metabolism and GAD activity may contribute to the apparent decrease in in vivo GABA synthesis caused by GBL.  相似文献   

15.
Applying GABA (1 microM-1 mM) to the soma of cultured lobster olfactory receptor neurons evokes an inward current (V(m) = -60 mV) accompanied by an increase in membrane conductance, with a half-effect of 487 microM GABA. The current-voltage relationship of this current is linear between -100 and 100 mV and reverses polarity at the equilibrium potential for Cl(-). The current is blocked by picrotoxin and bicuculline methiodide, and is evoked by trans-aminocrotonic acid, isoguvacine, muscimol, imidazole-4-acetic acid, and 3-amino-1-propanesulfonic acid, but not by the GABA(C)-receptor agonist cis-4-aminocrotonic acid and the GABA(B)-receptor agonist 3-aminopropylphosphonic. Applying GABA to the soma of the cells in situ reversibly suppresses the spontaneous discharge and substantially decreases the odor-evoked discharge. The effects of GABA on the cell soma in situ are antagonized by both picrotoxin and bicuculline methiodide. Taken together with evidence that GABA directly activates a chloride channel in outside-out patches excised from the soma of these neurons, we conclude that lobster olfactory receptor neurons express an ionotropic GABA receptor that can potentially regulate the output of these cells. Copyright Copyright 1999 S. Karger AG, Basel  相似文献   

16.
Abstract— The GABA-elevating agents, aminooxyacetic acid, hydrazine, and hydroxylamine, all possessed anticonvulsant properties, although to a widely varying degree. Aminooxyacetic acid was the most efficacious in delaying drug-induced seizures in mice whereas hydroxylamine brought about only a slight delay in the onset of seizures. The anticonvulsant action was observed against various convulsant agents regardless of whether the convulsant mechanism might involve a deranged GABA metabolism (allylglycine, isonicotinic acid hydrazide, hydrazine), an interference with GABA function (picrotoxin) or some other mechanism (pentylenetetrazol). The anticonvulsant action was not related in a simple manner to either GABA levels or glutamic acid decarboxylase (GAD) activities but the anomalous situation whereby seizures occurred when the GABA content of brain was above normal could be resolved on the basis of an expression which included changes in both GABA levels and GAD activity. The possibility was proposed that the anticonvulsant action of aminooxyacetic acid involved two separate mechanisms.  相似文献   

17.
The effect of cold and immobilization stress on presynaptic GABAergic autoreceptors was examined using the release of [3H]GABA (gamma-aminobutyric acid) from slices of rat striatum. It was found that in vitro addition of delta-aminolevulinic acid, as well as GABA agonists such as muscimol and imidazoleacetic acid, exhibited a significant suppression of the striatal release of [3H]GABA evoked by the addition of high potassium, whereas delta-aminovaleric acid had no significant effects on the evoked release. These suppressive actions were antagonized invariably by the GABA antagonists, bicuculline and picrotoxin, but not by the glycine antagonist, strychnine. Cholinergic agonists, such as pilocarpine and tetramethylammonium, also attenuated significantly the evoked release of [3H]GABA from striatal slices, while none of its antagonists, including atropine, hexamethonium and d-tubocurarine, affected the release. On the other hand, in vitro addition of dopamine receptor agents such as dopamine, apomorphine, and haloperidol, or the inhibitory amino acids, glycine, beta-alanine, and taurine failed to influence the evoked release of [3H]GABA from striatal slices. Application of a cold and immobilization stress for 3 h was found to induce a significant enhancement of the suppressive effects by muscimol and delta-aminolevulinic acid on the evoked release of [3H]GABA, without affecting that by pilocarpine and tetramethylammonium. These results suggest that the release of GABA from striatal GABA neurons may be regulated by presynaptic autoreceptors for this neuroactive amino acid, and may play a significant functional role in the exhibition of various symptoms induced by stress.  相似文献   

18.
An amino acid residue was found in M2 of gamma-aminobutyric acid (GABA) type A receptors that has profound effects on the binding of picrotoxin to the receptor and therefore may form part of its binding pocket. In addition, it strongly affects channel gating. The residue is located N-terminally to residues suggested so far to be important for channel gating. Point mutated alpha1beta(3) receptors were expressed in Xenopus oocytes and analyzed using the electrophysiological techniques. Coexpression of the alpha(1) subunit with the mutated beta(3) subunit beta(3)L253F led to spontaneous picrotoxin-sensitive currents in the absence of GABA. Nanomolar concentrations of GABA further promoted channel opening. Upon washout of picrotoxin, a huge transient inward current was observed. The reversal potential of the inward current was indicative of a chloride ion selectivity. The amplitude of the inward current was strongly dependent on the picrotoxin concentration and on the duration of its application. There was more than a 100-fold decrease in picrotoxin affinity. A kinetic model is presented that mimics the gating behavior of the mutant receptor. The point mutation in the neighboring residue beta(3)A252V resulted in receptors that displayed an about 6-fold increased apparent affinity to GABA and an about 10-fold reduced sensitivity to picrotoxin.  相似文献   

19.
家兔62只,用乌拉坦(700mg/kg)和氯醛醣(35mg/kg)静脉麻醉,三碘季铵酚制动,在人工呼吸下进行实验。用电刺激下丘脑近中线区的方法诱发室性期前收缩(HVE)。静脉注射安定(0.5mg/kg)可降低基础血压(BP),减弱刺激下丘脑引起升压反应(指收缩压峰值SBP_(max))和减少HVE。在双侧延髓腹外侧头端区(rVLM)微量注射氟安定(200μg溶于0.5μl中),γ-氨基丁酸(GABA)(6μg溶于0.5μl中)均能降低BP、SBP_(max)和减少HVE,若微量注射印防己毒素(7.5μg溶于0.5μl中)则可使BP上升并增多HVE。而于双侧延髓腹外侧尾端区(cVLM)微量注射同样剂量氟安定、GABA则无上述反应。安定降低BP、SBP_(max)和减少HVE的作用可被双侧rVLM区微量注射GABA受体拮抗剂荷包牡丹碱(3μg溶于0.5μl中)或印防己毒素所消除,但在双侧rVLM区微量注射甘氨酸受体拮抗剂士的宁(1μg溶于0.5μl中)、阿片受体拮抗剂纳洛酮(0.5μg溶于0.5μl中)、胆碱能阻断药阿托品(0.25μg溶于0.5μl中)、东莨菪碱(1.5μg溶于0.5μl中)后仍然存在。 上述结果提示,在双侧rVLM应用GABA受体拮抗剂可消除安定降低BP、SBP_(max)和减少HVE的作用,安定降低BP、SBP_(max)和减少HVE的作用可能通过GABA这一中间环节,而胆碱能受体、阿片受体、甘氨酸受体可能不起重要作用。  相似文献   

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