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 共查询到20条相似文献,搜索用时 125 毫秒
1.
金樱子花粉形态及营养成分研究   总被引:5,自引:0,他引:5  
金樱子花粉形态及营养成分研究刘剑秋,张清其,吴文珊(福建师范大学生物系,福州350007)STUDIESONMORPHOLOGYANDNUTRITIONCOMPOSITIONSOFPOLENOFROSALAEVIGATA¥LiuJiang-qiu;Z...  相似文献   

2.
棕背鼠最适生境及其主导因子分析THEOPTIMALBIOTOPEOFLARGE-TOOTHEDRAD-BACKEDVOLEANDTHEANALYSESOFITSMAINFACTORSKeywordsLarge-toothedrad-dackedvol...  相似文献   

3.
多胺对香蕉果实乙烯发生的影响   总被引:6,自引:0,他引:6  
多胺对香蕉果实乙烯发生的影响蒋跃明,张东林,李月标,陈芳,刘淑娴(中国科学院华南植物研究所,广州510650)EFFECTSOFPOLYAMINESONTHEETHYLENEEVOLUTIONOFBANANAFRUITSJiangYue-ming;Z...  相似文献   

4.
植物抗寒剂防止膜脂过氧化的研究孙龙华,简令成,卢存福,曹丽(中国科学院植物研究所,北京100044)STUDIESONTHEPREVENTIONOFPLANTCOLD-RESISTERFROMPEROXIDATIONOFMEMBRANELIPIDS¥...  相似文献   

5.
黄花胡椒的化学成分   总被引:2,自引:0,他引:2  
黄花胡椒的化学成分张可,陈昌祥,邓富(中国科学院昆明植物研究所植物化学开放实验室,昆明650204)(云南中医学院,昆明650031)CHEMICALCONSTITUENTSOFPIPERFLAVIFLORUM¥ZHANGKe;CHENChang-X...  相似文献   

6.
本文报道以人Epstein-Barr病毒的潜代膜蛋白基因BNLF-1作为目标基因,插入至逆转录病毒载体pZipNeoSV(x)的克隆位点上,由此获得重组逆转录病毒载体pZipNeoSV(x)-LMP及其反义载体pZipNeoSV(x)-anti-LMP,通过质粒DNA的电转染和G418培养基筛选,然后对10个抗性克隆进行基因整合分析、获得6个含MLV-LTR/BVLF-1融合基因的阳性克隆,采用N  相似文献   

7.
舟山岛与金华北山社鼠肥满度的比较与分析   总被引:5,自引:0,他引:5  
舟山岛与金华北山社鼠肥满度的比较与分析THECOMPARISONANDANALYSISOFRELATIVEFATNESSOFRATTUSNIVIVENTERBETWEENZHOUSHANISLANDANDJINHUANORTHMOUNTAINKeyw...  相似文献   

8.
荔枝胚胎发育的研究   总被引:4,自引:0,他引:4  
荔枝胚胎发育的研究邱燕平,张展薇,丘荣熙(广东省农科院果树所,广州510650)(广东教育学院,广州510303)STUDYONEMBRYOANDENDOSPERMDEVELOPMENTOFLITCHICHINENSISSONN¥QiuYan-pin...  相似文献   

9.
池塘养殖环境中底质-水界面营养盐扩散通量的现场测定   总被引:3,自引:0,他引:3  
孙耀 《生态学报》1996,16(6):664-669
池塘养殖环境中底质-水界面营养盐扩散通量的现场测定FIELDDETERMINATIONOFDIFFUSIONFLUXOFNUTRIENTSFROMSEDIMENT-WATERINTERFACEOFCULTUREPOND¥SunYao(YellowSe...  相似文献   

10.
中国科学院动物研究所兽类标本馆藏模式标本名录   总被引:1,自引:0,他引:1  
罗彤 《动物分类学报》1998,23(3):333-335
中国科学院动物研究所兽类标本馆藏模式标本名录CATALOGUEOFTHEMAMMALTYPESPECIMENSPRESERVEDINTHEMAMMALCOLLECTIONOFTHEINSTITUTEOFZOOLOGY,CHINESEACADEMYOF...  相似文献   

11.
Zheng C  Wang MY 《生理学报》2012,64(2):155-162
Descending activation pathways in spinal cord are essential for inducing and modulating autokinesis, but whether the effects of general anesthetic agents on the descending pathways are involved in initiation of skeletal muscle relaxation or not, as well as the underlying mechanisms on excitatory amino acid receptors still remain unclear. In order to explore the mechanisms underlying etomidate's effects on descending activation of spinal cord motoneurons (MNs), the conventional intracellular recording techniques in MNs of spinal cord slices isolated from neonatal rats (7-14 days old) were performed to observe and analyze the actions of etomidate on excitatory postsynaptic potential (EPSP) elicited by electrical stimulation of the ipsilateral ventrolateral funiculus (VLF), which was named VLF-EPSP. Etomidate at 0.3, 3.0 (correspond to clinical concentration) and 30.0 μmol/L were in turn perfused to MN with steadily recorded VLF-EPSPs. At low concentration (0.3 μmol/L), etomidate increased duration, area under curve and/or half-width of VLF-EPSP and N-methyl-D-aspartate (NMDA) receptor-mediated VLF-EPSP component (all P < 0.05), as well as amplitude, area under curve and half-width of non-NMDA receptor-mediated VLF-EPSP component (all P < 0.05), or decreased amplitude and area under curve of VLF-EPSP, its NMDA receptor component, and non-NMDA receptor component (all P < 0.05). However, at 3.0 and 30.0 μmol/L, it was only observed that etomidate exerted inhibitory effects on amplitude and/or duration and/or area under curve of VLF-EPSP (P < 0.05 or P < 0.01) with concentration- and time-dependent properties. Moreover, NMDA receptor-mediated VLF-EPSP component was more sensitive to etomidate at ≥ 3.0 μmol/L than non-NMDA receptor-mediated VLF-EPSP component did. As a conclusion, etomidate, at different concentrations, exerts differential effects on VLF-EPSP and glutamate receptors mediating the synaptic transmission of descending activation of MNs in neonatal rat spinal cord in vitro.  相似文献   

12.
In the guinea pig, EPSPs and population spikes were found to be generated in the apical dendrites of pyramidal neurons of middle and ventral hippocampus, in response to dorsal hippocampal commissure (PSD) stimulation, without any involvement of dentate gyrus granule cells of corresponding segments. These long-latency synaptic effects were evoked only by repetitive (0.2-2.0 c/sec) PSD stimulation and showed increasing latency in ventral direction. A cross section between dorsal and middle hippocampus was followed by the disappearance of the responses ventrally to the section. The results show that the postsynaptic discharge of dorsal pyramidal neurons is transferred to more ventral hippocampal segments by an intrahippocampal longitudinal association system.  相似文献   

13.
The character of dorsal horn motoneurons and interneurons evoked by stimulation of the dorsal root, and activity of Renshaw cells in response to stimulation of the ventral root were studied in albino rats in the lower lumbar segments of the spinal cord 5 days after sciatic nerve division. A significant increase in the mean amplitude of excitatory postsynaptic potentials of motoneurons was observed on the side of division of the nerve. No significant change in membrane potential and in the threshold of appearance of the action potential of these motoneurons took place. The mean number of action potentials and the duration of discharge of the Renshaw cells and dorsal horn interneurons likewise were not significantly changed.Dnepropetrovsk Medical Institute, Ukrainian Ministry of Health. Translated from Neirofiziologiya, Vol. 24, No. 3, pp. 306–314, May–June, 1992.  相似文献   

14.
In the tobacco hornworm caterpillar, tactile stimulation of sensory hairs located on the tip of a proleg (the planta) evokes ipsilateral or bilateral retraction of the prolegs in that segment. We have used electrophysiological and anatomical methods to investigate the excitatory neural pathways linking the planta hair afferents and the proleg retractor motoneurons (MNs). An important technical innovation was the development of an isolated proleg and desheathed ganglion preparation that permits rapid and reversible ionic manipulations and drug applications. Action potentials (spikes) in individual planta hair afferents produce time-locked excitatory postsynaptic potentials (EPSPs) in ipsilateral proleg MNs which appear to be chemically-mediated and monosynaptic: the EPSPs have a short and constant latency, they follow afferent spikes without failure, they are reversibly abolished in elevated Mg++ saline, and they persist in saline with elevated Mg++ and Ca++ levels. Planta hair afferents also excite ipsilateral MNs by polysynaptic pathways, and their excitation of contralateral proleg MNs is exclusively polysynaptic. Cobalt-staining of the proleg MNs and planta hair afferents shows that the afferents terminate in ventral neuropil, and the proleg MNs have an unusual ventral projection into this region. The ventral projection is on the ipsilateral side, which is consistent with the electrophysiological finding that time-locked EPSPs are found only from ipsilateral hairs. Two factors that contribute to the strong monosynaptic excitation of proleg MNs by ipsilateral planta hairs are the convergence of many hair afferents onto each MN, and the facilitation shown at each afferent-MN synapse. At least 6 afferents converge on each MN, and at short interspike intervals the afferent-evoked EPSPs are enhanced by as much as 400% by homosynaptic facilitation. The EPSP is abolished reversibly by the cholinergic antagonists curare and atropine, suggesting that the neurotransmitter at the synapse is acetylcholine (ACh). This is of particular interest because the ACh receptors of tobacco-feeding Manduca larvae are reported to be less nicotine-sensitive than those of other insects.  相似文献   

15.
Kerchner GA  Li P  Zhuo M 《IUBMB life》1999,48(3):251-256
Severe tissue or nerve injury can result in a chronic and inappropriate sensation of pain, mediated in part by the sensitization of spinal dorsal horn neurons to input from primary afferent fibers. Synaptic transmission at primary afferent synapses is mainly glutamatergic. Although a functioning excitatory synapse contains both alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproprionic acid (AMPA) and N-methyl-D-aspartate (NMDA) receptors in the postsynaptic membrane, recent evidence suggests that dorsal horn neurons contain some "silent" synapses, which exhibit purely NMDA receptor-mediated evoked postsynaptic currents and do not conduct signals at resting membrane potential. Serotonin, which is released onto dorsal horn neurons by descending fibers from the rostroventral medulla, potentiates sensory transmission by activating silent synapses on those neurons, i.e., by recruiting functional AMPA receptors to the postsynaptic membrane. This phenomenon may contribute to the hyperexcitability of dorsal horn neurons seen in chronic pain conditions.  相似文献   

16.
Wan YH  Wang YY  Dai F  Hu SJ 《生理学报》2004,56(4):550-557
本文描述了用明胶半包埋法制备带背根脊髓薄片的实验步骤,和在脊髓背角记录由初级传入纤维介导的突触后电流的可视膜片钳法。手术制备一段带背根的脊髓标本,并用20%的明胶包埋在琼脂块上,再用振动切片机切片获得带背根的脊髓薄片。通过红外线可视的引导,在脊髓背角神经元上建立全细胞封接模式。在钳制电压为-70mV条件下,记录自发的和背根刺激引起的兴奋性突触后电流。以传入纤维的传导速度与刺激阈值为指标,可以区分A样纤维与C样纤维兴奋性突触后电流。在钳制电压为0mV条件下,记录自发的和背根刺激引起的抑制性突触后电流。用5μmol/L的士宁或20μmol/L的荷包牡丹碱分离出γ-氨基丁酸能或甘氨酸能的抑制性突触后电流。用可视膜片钳方法可以准确测量脊髓背角神经元的突触后电流,从而研究初级传入突触的传递过程。更重要的是,在红外线可视观察的帮助下,建立膜片钳封接的成功率显著提高,同时也使记录研究脊髓背角深层神经元变得更加容易。本研究为探索初级传入突触传递过程提供了一个有效的方法。  相似文献   

17.
翟进  马如纯 《生理学报》1990,42(1):29-36
本文应用细胞内记录技术,观察了钙通道阻滞剂硝苯吡啶(nifedipine)对离体豚鼠腹腔神经节突触传递的影响,硝苯吡啶(0.1-10umol/L)不影响所检细胞的静息膜电位,膜电阻及细胞内刺激引起的动作电位,但能显著阻断N-型胆碱能的突触传递,并且这种作用可被低钙模拟、高钙拮抗,硝苯吡啶(10umol/L)也不影响突触后膜对乙酰胆碱(ACh)的敏感性;但在高钾克氏液中,能减少微小兴奋性突触后电位(mEPSPs)的频率;在低钙和高镁克氏液中,能减少量子含量,而对量子大小无影响。结果表明,治疗量的硝苯吡啶(0.1umol/L)通过阻滞突触前膜钙内流及ACh的量子性释放,产生突触阻断作用。这可能是硝苯吡啶降压机理的一个组成部分。  相似文献   

18.
M Jia  P G Nelson 《Peptides》1987,8(3):565-568
Monosynaptic excitatory post-synaptic potentials (EPSPs) evoked in spinal cord (SC) neurons by stimulation of dorsal root ganglion (DRG) neurons in cell cultures were reduced by perfusion application of the opiate peptide, Met-enkephalin (2-4 microM). In about 2/3 of cases examined, EPSPs evoked by stimulation of spinal cord cells were also reduced by Met-enkephalin. The effects were antagonized by concomitant perfusion with naloxone (1-2 microM) and recovered when perfusion with Met-enkephalin was stopped. Statistical analysis of synaptic responses indicated that the reduction of EPSP amplitude was due, at least to a major extent, to a decrease in presynaptic transmitter release.  相似文献   

19.
Effects induced in motoneurons and interneurons of the cervical enlargements of the cat spinal cord by stimulation of the lateral and ventral funiculi at the lower thoracic level were studied under conditions producing degeneration of fibers of descending brain systems. Stimulation of this sort evoked PSPs (mainly of mixed character) in 57 of 90 motoneurons tested. In nine motoneurons the primary response consisted of monosynaptic EPSPs evoked by activity of fibers of the lateral funiculus, and in the rest it consisted of polysyanptic (at least disynaptic) EPSPs and IPSPs. Polysynaptic effects arising in the neuron in response to stimulation of the lateral and ventral funiculi usually differed only quantitatively. The intensity of excitatory synaptic action on motoneurons of the proximal muscle (especially thoracid) was much greater than that on motoneurons of distal muscles. Nearly all motoneurons with no synaptic action belonged to the latter group. Stimulation of the lateral and ventral funculi facilitated synaptic action induced in motoneurons by stimulation of high-threshold segmental afferents and led to excitation of interneurons located in the vectral quadrant, and had no effect on interneurons in the dorsal regions of gray matter. These effects are regarded mainly as the result of excitation of long ascending propriospinal pathways in the cervical parts of the cord; it is also postulated that some of them are evoked by the arrival of activity along collaterals of descending propiospinal pathways to the neurons in this region.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 11, No. 4, pp. 339–347, July–August, 1979.  相似文献   

20.
Grigoryan G  Korkotian E  Segal M 《Hippocampus》2012,22(7):1635-1644
The effects of low concentrations of caffeine and ryanodine on field excitatory postsynaptic potentials (EPSPs) and long-term potentiation (LTP) were studied in CA1 region of slices of dorsal and ventral hippocampus (DH and VH, respectively). There was a striking difference between the two regions in the magnitude of effect of both drugs, as well as the ability to interact with a tetanic stimulation to produce LTP. Low concentration of caffeine (1 mM) produced a postsynaptic increase in the slope of population EPSPs in VH, and facilitated LTP in this region. Low concentration of ryanodine (0.2 μM) was able to convert short-term potentiation (STP) to LTP in VH only. These effects are postsynaptic and they reflect a higher concentration of ryanodine receptors (RyRs) in the VH compared to the DH.  相似文献   

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