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71.
Thérèse M. Delahunty Ji Y. Jiang Raiford T. Black Bruce G. Lyeth 《Neurochemical research》1995,20(4):405-411
In the fluid percussion model of traumatic brain injury (TBI), we examined muscarinic and metabotropic glutamate receptor-stimulated polyphosphoinositide (PPI) turnover in rat hippocampus. Moderate injury was obtained by displacement and deformation of the brain within the closed cranial cavity using a fluid percussion device. Carbachol and (±)-1-Aminocyclopentane-trans-1,3.-dicarboxylic acid (trans-ACPD)-stimulated PPI hydrolysis was assayed in hippocampus from injured and sham-injured controls at both 1 hour and 15 days following injury. At 1 hour after TBI, the response to carbachol was enhanced in injured rats by up to 200% but the response to trans-ACPD was diminished by as much as 28%. By contrast, at 15 days after TBI, the response to carbachol was enhanced by 25% and the response to trans-ACPD was enhanced by 73%. The ionotropic glutamate agonists N-methyl-D-aspartate (NMDA), and -amino-3 hydroxy-5-methyl-4-isoxazolepropionate (AMPA), did not increase PPI hydrolysis in either sham or injured rats and injury did not alter basal hydrolysis. Thus, hippocampal muscarinic and metabotropic receptors linked to phospholipase C are differentially altered by TBI.Abbreviations used TBI
traumatic brain injury
- EAA
excitatory amino acids
- PPI
polyphosphoinositides
- IP
inositol phosphates
- NMDA
N-methyl-D-aspartate
- AMPA
-amino-3-hydroxy-5-methylisoxazole-4-propionate
- trans-ACPD
(±)-1-Aminocyclopentanetrans-1,3-dicarboxylic acid
- LTP
long term potentiation 相似文献
72.
73.
海马内生长抑素与γ-氨基丁酸在大鼠穿梭箱主动回避反应中的作用 总被引:1,自引:0,他引:1
本实验以大鼠穿梭箱主动回避反应(AAR)的习得和消退为学习记忆的指标,研究了海马内生长抑素(SS)和γ-氨基丁酸(GABA)在学习记忆中的作用。结果如下:(1)经训练而建立了AAR的大鼠,其海马内SS较对照组显著增高,而海马内GABA含量却明显降低;(2)海马内注入SS的耗竭剂半胱胺(Cys,20g/L)使大鼠AAR的习得受到明显损害,AAR的消退显著加速,海马内SS明显降低,而GABA含量却显著升高;(3)海马内注入GABA(200g/L)使大鼠AAR的消退显著加速的同时,其海马内SS含量亦显著降低。由此表明,海马内SS可能有促进学习记忆的作用,而海马内GABA升高则有相反的效应;二者在海马调控学习记忆过程中具有重要作用。 相似文献
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78.
Michael Fernandes Gaddo Onesti Roberto Fiorentini Giuseppe Bellini Anne B. Gould Kwan Eun Kim Charles Swartz 《Life sciences》1977,20(4):623-626
Renal hypertension was induced by ligation of the aorta between renal arteries in rats sympathectomized with 6-hydroxydopamine. In the early phase, equally severe hypertension developed in the denervated group as compared to innervated controls. Later, blood pressure was lower in the denervated rats. Initially, increases in plasma renin were seen in both groups; the levels, however, were markedly lower in the denervated rats. Later, the renin levels were similar and not different from baseline. It is concluded that adrenergic neural activity is not essential in the development of renal hypertension; the maintenance of the chronic state, however, depends in part on adrenergic innervation. 相似文献
79.
Summary Evidence is presented from a preliminary study showing that C-13 N.M.R. spectroscopy is a useful new tool for the elucidation of the structure of soil organic matter. 相似文献
80.
Jiří Ponert 《Folia Geobotanica》1977,12(1):9-22
Studies of the Adjarian flora resulted in a detailed classification of the ergasiophygophytes, based mainly on the degree of their naturalization: (1) The ephemeroergasiophygophytes display unstable naturalization both in artificial and natural habitats, and disappear after only a few growing seasons. (2) The deuteroergasiophygophtes show stable naturalization in anthropogenic habitats. (3) The protoergasiophygophytes are distinguished by uncertain stability of naturalization in natural habitats, and, if firmly naturalized on a certain spot, they lack any tendency to further spreading. (4) The autergasiophygophytes tend to spread in natural habitats. (5) The aggressive ergasiophygophytes transform natural vegetation in new plant communities, and can become dominant species in these communities. New terms, viz. emphemeroxenophytes, protoneophytes, non-aggressive neophytes, slightly aggressive neophytes, and postneophytes with vegetative reproduction have also been introduced to express diverse features of the xenophytes. 相似文献