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131.
目的:探讨航海刺激对大鼠七氟烷麻醉敏感性的影响,为海上环境下七氟烷的合理使用提供依据。方法:以大鼠条件性厌食症作为判断指标,采用仿制Crampton旋转刺激器制作大鼠运动病模型。①60只SD大鼠随机分为对照组(n=15)和旋转组(n=45),观测2组大鼠的活动和行为变化、达到睡眠和麻醉状态所需七氟烷浓度以及麻醉苏醒时间。②32只SD大鼠随机分为四组(n=8):对照(Ⅰ)组、旋转(Ⅱ)组、麻醉(Ⅲ)组和旋转后再麻醉(Ⅳ)组,分别检测4组大鼠之大脑皮层、下丘脑和海马组织的乙酰胆碱、去甲肾上腺素、г-氨基丁酸及谷氨酸含量。结果:对照组大鼠达到睡眠和麻醉状态所需七氟烷浓度分别为1.74%±0.05%和3.54%±0.05%,旋转组分别为1.51%±0.06%和3.14%±0.08%,旋转组大鼠达到睡眠和麻醉状态所需七氟烷浓度明显降低(P<0.01)。神经递质变化以Ⅲ组大鼠各递质含量显著降低为其主要特点,在大脑皮层和海马组织中表现尤为明显(P<0.01)。Ⅱ组大鼠大脑皮层Ach显著升高,海马组织NE、GABA明显降低。Ⅳ组变化趋势更接近于Ⅱ组,即以旋转刺激的影响更为明显。结论:模拟航海刺激可明显增加大鼠对七氟烷麻醉的敏感性。 相似文献
132.
Shireesh Srivastava Yoshihiro Kashiwaya Xuesong Chen Jonathan D. Geiger Robert Pawlosky Richard L. Veech 《Journal of neurochemistry》2012,123(5):668-675
Rapid inactivation of metabolism is essential for accurately determining the concentrations of metabolic intermediates in the in vivo state. We compared a broad spectrum of energetic intermediate metabolites and neurotransmitters in brains obtained by microwave irradiation to those obtained by freeze blowing, the most rapid method of extracting and freezing rat brain. The concentrations of many intermediates, cytosolic free NAD(P)+/NAD(P)H ratios, as well as neurotransmitters were not affected by the microwave procedure. However, the brain concentrations of ATP were about 30% lower, whereas those of ADP, AMP, and GDP were higher in the microwave‐irradiated compared with the freeze‐blown brains. In addition, the hydrolysis of approximately 1 μmol/g of ATP, a major in vivo Mg2+‐binding site, was related to approximately five‐fold increase in free [Mg2+] (0.53 ± 0.07 mM in freeze blown vs. 2.91 mM ± 0.48 mM in microwaved brains), as determined from the ratio [citrate]/[isocitrate]. Consequently, many intracellular properties, such as the phosphorylation potential and the ?G' of ATP hydrolysis were significantly altered in microwaved tissue. The determinations of some glycolytic and TCA cycle metabolites, the phosphorylation potential, and the ?G' of ATP hydrolysis do not represent the in vivo state when using microwave‐fixed brain tissue. 相似文献
133.
Matej Repič Robert Vianello Miha Purg Fernanda Duarte Paul Bauer Shina C. L. Kamerlin Janez Mavri 《Proteins》2014,82(12):3347-3355
Monoamine oxidases (MAOs) A and B are flavoenzymes responsible for the metabolism of biogenic amines such as dopamine, serotonin and noradrenaline. In this work, we present a comprehensive study of the rate‐limiting step of dopamine degradation by MAO B, which consists in the hydride transfer from the methylene group of the substrate to the flavin moiety of the FAD prosthetic group. This article builds on our previous quantum chemical study of the same reaction using a cluster model (Vianello et al., Eur J Org Chem 2012; 7057), but now considering the full dimensionality of the hydrated enzyme with extensive configurational sampling. We show that MAO B is specifically tuned to catalyze the hydride transfer step from the substrate to the flavin moiety of the FAD prosthetic group and that it lowers the activation barrier by 12.3 kcal mol?1 compared to the same reaction in aqueous solution, a rate enhancement of more than nine orders of magnitude. Taking into account the deprotonation of the substrate prior to the hydride transfer reaction, the activation barrier in the enzyme is calculated to be 16.1 kcal mol?1, in excellent agreement with the experimental value of 16.5 kcal mol?1. Additionally, we demonstrate that the protonation state of the active site residue Lys296 does not have an influence on the hydride transfer reaction. Proteins 2014; 82:3347–3355. © 2014 Wiley Periodicals, Inc. 相似文献
134.
Development of the larval muscle system in the mussel Mytilus trossulus (Mollusca,Bivalvia) 总被引:1,自引:0,他引:1
In the present study we examined muscle development throughout the complete larval cycle of the bivalve mollusc, Mytilus trossulus. An immunofluorescence technique and laser scanning confocal microscopy were used in order to study the organization of the muscle proteins (myosin, paramyosin, twitchin, and actin) and some neurotransmitters. The appearance of the muscle bundles lagged behind their nervous supply: the neuronal elements developed slightly earlier (by 2 h) than the muscle cells. The pioneer muscle cells forming a prototroch muscle ring were observed in a completed trochophore. We documented a well‐organized muscle system that consisted of the muscle ring transforming into three pairs of velar striated retractors in the early veliger. The striations were positive for all muscle proteins tested. Distribution of FMRFamide and serotonin (5‐HT) immunocytochemical staining relative to the muscle ring differed significantly: 5‐HT‐immunioreactive cells were situated in the center of the striated muscle ring, while Phe‐Met‐Arg‐Phe‐NH2 neuropeptide FMRFamid immunoreactive fibers were located in a distal part of this ring. Our data showed clearly that the muscle proteins and the neurotransmitters were co‐expressed in a coordinated fashion in a continuum during the early stages of the mussel development. Our study provides the first strong evidence that mussel larval metamorphosis is accompanied by a massive reorganization of striated muscles, followed by the development of smooth muscles capable of catch‐contraction. 相似文献
135.
Verena Rieger Yvan Perez Carsten H. G. Müller Elisabeth Lipke y Sombke Bill S. Hansson Steffen Harzsch 《Invertebrate Biology》2010,129(1):77-104
Abstract. We examined the brain architecture in different species of Chaetognatha using immunofluorescence methods with a set of nervous system markers and confocal laser-scan microscopic analysis. These markers include antibodies against synaptic proteins, RFamide-related peptides, and tyrosinated tubulin, as well as a marker of cell nuclei. Furthermore, we present a 3D reconstruction based on histological section series. Our results expand the previous knowledge on neuroanatomy in Chaetognatha. We suggest a structural and functional subdivision of the rather complex chaetognath brain into two domains, a posterior domain that may be primarily involved in the integration of sensory input, and an anterior domain that may be involved in the control of the mouthparts and the anterior part of the digestive system. Immunolocalization of a neuropeptide suggests the presence of an identifiable group of neurons associated with the brain of all species examined here. However, our data also reveal a certain degree of interspecific variation and divergence within the Chaetognatha concerning, for example, the pattern of nerves branching off the brain and the proportional sizes of the various neuropil compartments. We compare our data to brain architecture in various other representatives of Protostomia and Deuterostomia. The chaetognath brain fits within the range of structural variation encountered in protostomian brains, and we cannot find any brain characteristics that would argue in favor of placing chaetognaths outside of the Protostomia. Rather, we see the circumoral arrangement of their cephalic nervous system as an argument that suggests protostome affinities. 相似文献
136.
Gouaux E 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2009,364(1514):149-154
Synaptic transmission at chemical synapses requires the removal of neurotransmitter from extracellular spaces. At synapses in the central nervous system, this is accomplished by sodium-coupled transport proteins, integral membrane proteins that thermodynamically couple the uptake of neurotransmitter to the uptake of sodium and, in some cases, the uptake and export of additional ions. Recent X-ray crystallographic studies have revealed the architecture of the two major families of neurotransmitter transporters and, together with additional biochemical and biophysical studies, have provided insights into mechanisms of ion coupling, substrate uptake, and inhibition of transport. 相似文献
137.
138.
139.
A. I. Gladkova 《Neurophysiology》2000,32(1):57-61
The review considers the published data and the results obtained by the author on the role of monoamines (serotonin, dopamine,
and noradrenaline) in the control of male sexual behavior. In the above respect, the central mechanisms of action of the neurotransmitters
are discussed. 相似文献
140.
Plasma membrane dehydrogenases in rat brain synaptic membranes. Multiplicity and subunit composition
J. L. Dreyer 《Journal of bioenergetics and biomembranes》1990,22(5):619-633
Plasma membrane redox enzymes have been investigated in synaptic membranes from rat brain nerve terminals. UV-Vis spectra of intact synaptic plasma membranes are presented and the presence of ab-type cytochrome, detectable at 77°K and sensitive to NADH or NADPH, is shown. The molecular characterization of rat synaptic NADH-dehydrogenases was further performed on solubilized enzymes using a recently developed nondissociating polyacrylamide gel electrophoresis technique. Synaptic plasma membranes were solubilized with 1% sodium cholate or Triton X-114 and centrifuged. The supernatant retained over 60% of the NADH-dehydrogenase activity, tested with either DCIP or ferricyanide as substrates, together with NADH. Both enzyme activities were insensitive toward rotenone. This extraction procedure also solubilized about 50% of the proteins. When submitted to polyacrylamide gel electrophoresis under nondenaturing conditions and stained for NADH-dehydrogenase activity, five bands of different mobilities were detected. The multiple NADH-dehydrogenases of synaptic plasma membranes were investigated by means of band excision and the five excised bands each submitted to amino acid analysis and to 2-D electrophoresis. The subunit composition of each band was then deduced, together with the molecular weight and pI of each respective subunit. NADH-dehydrogenases have also been purified by means of FPLC on Mono-P (chromatofocusing) followed by gel filtration on Superose 12. NADH-Dehydrogenase IV and V could be purified in their active forms by this approach.Abbreviations DCIP
dichlorophenol-indophenol
- FPLC
fast protein liquid chromatography. 相似文献