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921.
The enhanced metabolism of phosphoinositides, which is associated with a wide variety of stimuli and physiological responses, has been studied intensively. Berridge and his collaborators demonstrated that the first measurable reaction following cell membrane receptor activation is a rapid hydrolysis of phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2), and that the product of this reaction, inositol 1,4,5-trisphosphate (Ins(1,4,5)P3), could cause a release of non-mitochondrial calcium. These findings have been verified in other systems. Although the relationship between the hydrolysis of PtdIns(4,5)P2 and the mobilization of intracellular calcium was clearly demonstrated, the direct link between Ins(1,4,5)P3 production and the physiological response was only implied. We have investigated the possibility that the intracellular release of Ins(1,4,5)P3 mediates the muscarinic-cholinergic response is Xenopus oocytes, and we show here that intracellularly injected Ins(1,4,5)P3 mimics the muscarinic depolarizing chloride current in Xenopus oocytes. This is the first demonstration of a direct link between phosphoinositides metabolism and a neuro-transmitter-induced physiological response. 相似文献
922.
Phencyclidine (PCP), when given to mice, induces general hyperactivity and rapid circling, similar to that caused by morphine. These effects are partially antagonized by naloxone. 相似文献
923.
西部农业信息化建设问题的探讨 总被引:3,自引:0,他引:3
西部农业信息化水平低下制约着西部农业的发展。物质基础薄弱、信息意识淡薄、信息人才及资金短缺是造成西部农业信息化水平低下的原因。为加快西部信息化农业建设,应该从更新观念、加大政府支持力度、利用有限资源进行信息化基础建设、重视人才资源的开发、培育信息产品市场、加强农业应用系统和信息化农业技术的研究、加强示范应用体系等方面入手。 相似文献
924.
Structure of a phage 434 Cro/DNA complex 总被引:24,自引:0,他引:24
Comparison of the crystal structure of a complex of the phage 434 Cro protein and a synthetic DNA operator with the complex of the same operator and the 434 repressor DNA-binding domain shows different DNA conformations in the two structures. Binding of the protein determines the precise conformation of the DNA in each case. 相似文献
925.
9-Methyl-7-bromoeudistomin D, a potent inducer of calcium release from sarcoplasmic reticulum of skeletal muscle 总被引:1,自引:0,他引:1
The Ca2+-releasing action of several derivatives of eudistomin D isolated from a marine tunicate was compared with that of caffeine. It was found that 9-methyl-7-bromoeudistomin D was approximately 1000 times more potent than caffeine in causing Ca2+ release from the sarcoplasmic reticulum. 相似文献
926.
Antibody to tumor necrosis factor (TNF) reduces endotoxin fever 总被引:2,自引:0,他引:2
Antibody to tumor necrosis factor (TNF), injected intravenously, reduced endotoxin fever in the rabbit. The fever-reducing effect was apparent in the latter half of the febrile response. 相似文献
927.
The origin of human language, and in particular the question of whether or not Neanderthal man was capable of language/speech, is of major interest to anthropologists but remains an area of great controversy. Despite palaeoneurological evidence to the contrary, many researchers hold to the view that Neanderthals were incapable of language/speech, basing their arguments largely on studies of laryngeal/basicranial morphology. Studies, however, have been hampered by the absence of unambiguous fossil evidence. We now report the discovery of a well-preserved human hyoid bone from Middle Palaeolithic layers of Kebara Cave, Mount Carmel, Israel, dating from about 60,000 years BP. The bone is almost identical in size and shape to the hyoid of present-day populations, suggesting that there has been little or no change in the visceral skeleton (including the hyoid, middle ear ossicles, and inferentially the larynx) during the past 60,000 years of human evolution. We conclude that the morphological basis for human speech capability appears to have been fully developed during the Middle Palaeolithic. 相似文献
928.
Y. Tomita K. Himeno K. Nomoto H. Endo T. Hirohata 《Cellular and molecular life sciences : CMLS》1985,41(1):92-93
Summary Intraperitoneal administration of vitamin A into the BALB/c mice inoculated with a syngeneic fibrosarcoma, Meth A, caused a remarkable augmentation of tumor rejection. A cell-depletion technique revealed that the primary effector cells responsible for the augmented rejection were Thy-1 positive, Lyt-1 negative, Lyt-2 positive lymphocytes, suggesting the involvement of cytotoxic lymphocytes.This work was supported in part by a Grant-in-Aid for scientific research from the Ministry of Education, Science and Culture, Japan, and in part by a Grant-in-Aid for cancer research from the Fukuoka Cancer Society, Japan.We thank Mr M. Fujiki and Miss A. Maeda for excellent technical assistance. 相似文献
929.
J. E. Décombaz B. Reffet Y. Bloemhard 《Cellular and molecular life sciences : CMLS》1990,46(5):457-458
Summary To test the effect of L-carnitine on glycogen sparing when fat oxidation is increased, 100 mg/kg/d were given to rats orally for 3 days, resulting in 1.8-fold higher muscle carnitine levels. Even when FFA were raised by heparin-stimulated lipolysis, the rate of glycogen degradation was not reduced during exercise. 相似文献
930.
J. Kobayashi Y. Ohizumi H. Nakamura Y. Hirata 《Cellular and molecular life sciences : CMLS》1986,42(10):1176-1177
Summary A novel bromine-containing pyrrole compound, hymenidin, has been isolated from the Okinawan marine spongeHymeniacidon sp. as a potent antagonist of serotonergic receptors and its structure elucidated using spectral data. 相似文献