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941.
In this issue of Neuron, Small and colleagues used fMRI to find evidence for a neural segregation of two dimensions underlying human gustatory experience: intensity and valence. These results join several recent reports that challenge long-held notions regarding amygdaloid representation of negatively valenced events. 相似文献
942.
Owens AP Nadin A Talbot AC Clarke EE Harrison T Lewis HD Reilly M Wrigley JD Castro JL 《Bioorganic & medicinal chemistry letters》2003,13(22):4143-4145
In this paper, we describe the development of a novel series of high affinity, orally bioavailable 3-amino-1,4 benzodiazepine-based gamma-secretase inhibitors for the potential treatment of Alzheimer's disease. We disclose structure-activity relationships based around the 1, 3 and 5 positions of the benzodiazepine core structure. 相似文献
943.
944.
Röver S Wichmann J Jenck F Adam G Cesura AM 《Bioorganic & medicinal chemistry letters》2000,10(8):831-834
We have investigated 8-cycloalkyl-1-phenyl-1,3,8-triaza-spiro[4.5]decan-4-o nes as ligands for the ORL1 receptor. These unsophisticated, achiral compounds show remarkable affinity for the ORL1 receptor. Optimizing for selectivity we show that the maximum of affinity and selectivity versus the other opioid receptors is achieved for 8-cyclodecyl-1-phenyl-1,3,8-triaza-spiro[4.5]decan-4-o ne 2e and 8-(cis-4-isopropyl-cyclohexyl)-1-phenyl-1,3,8-triaza-spiro[4.5] decan-4-one 2q. The identified compounds (2e, 2q) are more or less equipotent to the natural ligand itself, both in the binding assay and in the functional GTPgammaS assay. 相似文献
945.
Phospholipases A2 in Ischemic and Toxic Brain Injury 总被引:3,自引:0,他引:3
Phospholipases A2 (PLA2s) regulate hydrolysis of fatty acids, including arachidonic acid, from the sn-2 position of phospholipid membranes. PLA2 activity has been implicated in neurotoxicity and neurodegenerative processes secondary to ischemia and reperfusion and other oxidative stresses. The PLA2s constitute a superfamily whose members have diverse functions and patterns of expression. A large number of PLA2s have been identified within the central nervous systems of rodents and humans. We postulated that group IV large molecular weight, cytosolic phospholipase A2 (cPLA2) has a unique role in neurotoxicity associated with ischemic or toxin stress. We created mice deficient in cPLA2 and tested this hypothesis in two injury models, ischemia/reperfusion and MPTP neurotoxicity. In each model cPLA2 deficient mice are protected against neuronal injury when compared to their wild type littermate controls. These experiments support the hypothesis that cPLA2 is an important mediator of ischemic and oxidative injuries in the brain. 相似文献
946.
Chalconoids from Fissistigma bracteolatum 总被引:1,自引:0,他引:1
Phytochemical studies on the leaves of Fissistigma bracteolatum yielded besides the two known compounds 2-hydroxy-3,4,6-trimethoxychalcone (1) and 5,7,8-trimethoxyflav-3-ene (2), five new chalconoids 2-hydroxy-3,4,6-trimethoxychalcene (3), 2-hydroxy-3,4,6-trimethoxydihydrochalcone (4), 2'-hydroxy-3',4',6'-trimethoxydihydrochalcone (5), 2'-hydroxy-3',4',6'-trimethoxy-beta'-methoxychalcane (6) and 2'-hydroxy-3',4',6'-trimethoxy-beta'-ethoxychalcane (7). The structures of these compounds were determined by mass and NMR spectroscopic methods. 相似文献
947.
Evolutionary genetics of self-incompatibility in the Solanaceae 总被引:2,自引:0,他引:2
The self-incompatibility (S) gene in flowering plants has long been appreciated as an example of extreme allelic polymorphism maintained by frequency-dependent selection. Recent studies of population samples of S-allele sequences obtained by RT-PCR from five species of Solanaceae now reveal a picture of conspicuous inter-specific variation in both S-allele number and age. Explanations for this variation are examined with reference to current theory. We propose that changes in species' effective population size, particularly those associated with the evolution of different life histories, best account for interspecific differences in both the number and average age of S alleles. 相似文献
948.
Joanna Malicka Magorzata Groth Cezary Czaplewski Regina Kasprzykowska Adam Liwo Leszek ankiewicz Wieslaw Wiczk 《Letters in Peptide Science》1998,5(5-6):445-447
The probable conformations of two cyclic enkephalin analogs, DNS-cyclo[D-Dab-Gly-Trp-Leu] (I) and DNS-cyclo[D-Dab-Gly-Trp-D-Leu] (II) (DNS = dansyl), were determined by combining the results of NOE, vicinal coupling constant and fluorescence energy transfer measurements with theoretical calculations. The common feature of the conformations for both peptides is the presence of a -turn at residues 2 and 3. 相似文献
949.
950.
An interplay among experimental studies of protein synthesis, evolutionary theory, and comparisons of DNA sequence data has shed light on the roles of natural selection and genetic drift in ‘silent’ DNA evolution. 相似文献