Choline: high-affinity uptake by rat brain synaptosomes   总被引：35，自引：0，他引：35  

H I Yamamura  S H Snyder 《Science (New York, N.Y.)》1972,178(61):626-628

Synaptosomes from rat brain accumulate choline by two kinetically distinct processes, a high-affinity uptake system [Michaelis constant (K(m)) = 1 x 10(-6)M], and a low-affinity system (K(m) = 9 x 10(-5)M). The high-affinity uptake system requires sodium, and is associated with considerable formation of acetylcholine. The low-affinity uptake system is less dependent on sodium, and does not appear to be associated with a marked degree of acetylcholine formation. The high-affinity choline uptake appears to represent selective choline accumulation by cholinergic neurons.  相似文献   

Orality, preference behavior, and reinforcement value of nonfood object in monkeys with orbital frontal lesions   总被引：1，自引：0，他引：1  

C M Butter  J A McDonald  D R Snyder 《Science (New York, N.Y.)》1969,164(885):1306-1307

Monkeys with orbital frontal ablation, compared with sham-operated controls, showed enhancement of oral tendencies toward nonfood items. Further, unlike the controls, they persistently performed an instrumental response for one of these nonfood items. On the other hand, the lesioned monkeys did not show altered preferences for food versus nonfood items. These findings suggest that reinforcement value and preferential ordering are dissociated by orbital frontal ablation.  相似文献   

RELATION OF DUAL PHENOMENON IN PENICILLIUM NOTATUM TO PENICILLIN PRODUCTION     

Hansen HN  Snyder WC 《Science (New York, N.Y.)》1944,99(2570):264-265

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Hypoxia, fertilizer, and the Gulf of Mexico     

Snyder CS 《Science (New York, N.Y.)》2001,292(5521):1485-1486

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Niche partitioning increases resource exploitation by diverse communities     

Finke DL  Snyder WE 《Science (New York, N.Y.)》2008,321(5895):1488-1490

Classical ecological theory suggests that the coexistence of consumer species is fostered by resource-use differences, leading to greater resource use in communities with more species. However, explicit empirical support for this idea is lacking, because resource use by species is generally confounded with other species-specific attributes. We overcame this obstacle by co-opting behavioral plasticity in food choice among a group of animal consumers, allowing us to manipulate patterns of resource use while controlling for the effects of species identity and diversity. Within an aphid-parasitoid-radish community, we created a fully factorial manipulation of consumer resource-use breadth (specialist versus generalist) and species diversity (one versus three species) and found that resource exploitation improved with greater specialist, but not generalist, diversity. Therefore, resource partitioning, and not diversity per se, fostered greater overall resource consumption in our multispecies consumer communities.  相似文献   

Mariner v flight past venus     

Snyder CW 《Science (New York, N.Y.)》1967,158(3809):1665-1669

On 19 October 1967 the Mariner V spacecraft passed by Venus 10,151 kilometers from the center of the planet; the gravitational field, atmosphere, ionosphere, hydrogen corona, and interaction with the solar wind were observed.  相似文献   

Requirement for DARPP-32 in progesterone-facilitated sexual receptivity in female rats and mice     

Mani SK  Fienberg AA  O'Callaghan JP  Snyder GL  Allen PB  Dash PK  Moore AN  Mitchell AJ  Bibb J  Greengard P  O'Malley BW 《Science (New York, N.Y.)》2000,287(5455):1053-1056

DARPP-32, a dopamine- and adenosine 3',5'-monophosphate (cAMP)-regulated phosphoprotein (32 kilodaltons in size), is an obligate intermediate in progesterone (P)-facilitated sexual receptivity in female rats and mice. The facilitative effect of P on sexual receptivity in female rats was blocked by antisense oligonucleotides to DARPP-32. Homozygous mice carrying a null mutation for the DARPP-32 gene exhibited minimal levels of P-facilitated sexual receptivity when compared to their wild-type littermates. P significantly increased hypothalamic cAMP levels and cAMP-dependent protein kinase activity. These increases were not inhibited by a D1 subclass dopamine receptor antagonist. P also enhanced phosphorylation of DARPP-32 on threonine 34 in the hypothalamus of mice. DARPP-32 activation is thus an obligatory step in progestin receptor regulation of sexual receptivity in rats and mice.  相似文献   

A STUDY IN BIOKINETICS     

Snyder CD 《Science (New York, N.Y.)》1931,74(1923):443-449

In the foregoing pages the writer has attempted to point out first, the importance to physiologists of the discovery and application to their problems of a unit of physiological activity to serve as a universal measure of life processes. Second, a survey of the field of excitation and response points to the probability that electron transfers are involved in every case and, therefore, that such a standard of measure, if ever determined, will probably involve terms of radiational units. Third, a brief statement of some of the laws of radiation that seem to be involved is given, together with a sketch of the radiation hypothesis of chemical thermal reaction. Fourth, an analysis of the data of a few physiological processes is then presented, the results of which strongly suggest the possibility that the influence of temperature upon living processes may be due to dark-field radiations quite as much as the photochemical effects in living processes are due to radiation of visible light.  相似文献   

Regulation of gene expression by a metabolic enzyme     

Hall DA  Zhu H  Zhu X  Royce T  Gerstein M  Snyder M 《Science (New York, N.Y.)》2004,306(5695):482-484

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Brain histamine: rapid apparent turnover altered by restraint and cold stress   总被引：1，自引：0，他引：1  

K M Taylor  S H Snyder 《Science (New York, N.Y.)》1971,172(987):1037-1039

Histamine content of rat brain was lowered quickly by inhibitors of histidine decarboxylase, suggesting that a portion of brain histamine turns over rapidly. Restraint and exposure to cold also reduced brain histamine levels and markedly augmented its formation in the hypothalamus.  相似文献