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971.
972.
973.
Jeffery D. Steketee Caryn D. Striplin Thomas F. Murray Peter W. Kalivas 《Journal of neurochemistry》1992,58(3):811-816
Inhibitory regulation of dopamine neurons is mediated by dopamine autoreceptor and gamma-aminobutyric acidB receptor opening of potassium channels. Increased potassium conductance by either receptor is G protein dependent. To evaluate the role of G proteins in vivo, pertussis toxin (PTX) was microinjected into the A10 dopamine region and changes in dopamine metabolism and synthesis measured. PTX produced an elevation in dopamine metabolism and synthesis in the A10 region and nucleus accumbens for up to 4 days after injection. By day 7 the levels of the dopamine precursor and metabolites had returned to normal. A less consistent increase was also measured in the A9 dopamine region and the prefrontal cortex. Although dopamine synthesis and metabolism had returned to normal by day 7, the in vitro ADP-ribosylation of G proteins in the A10 region by PTX remained depressed by approximately 50% from day 1 to day 14 after administration, returning to normal by day 30. The data suggest that in vivo ribosylation of G proteins may lead to a short-term attenuation of the tonic inhibitory control of dopamine neurons, which can be compensated for by PTX-insensitive mechanisms. 相似文献
974.
Michael Gschwendt 《Biochimica et Biophysica Acta (BBA)/General Subjects》1975,399(2):395-402
Nafoxidine and CI-628, two well known antiestrogenic compounds, reduce the stimulating effect of estradiol on the estrogen-binding capacity of the liver chromatin from roosters. In vitro both antiestrogens compete with [3H] estradiol for the binding sites on the liver chromatin. They inhibit the estrogen-induced synthesis of egg yolk proteins (vitellogenin) and fail to induce this estrogen-specific protein synthesis by themselves. They show the ability, however, to increase the estrogen-binding sites on the liver chromatin to some extent. 相似文献
975.
Summary In a study involving twenty upland rice genotypes, the induction of iron chlorosis was found to be more by superphosphate
application than due to lime incorporation into an alfisol soil under greenhouse conditions in GI tray-grown seedlings as
quantified by two parameters viz., total chlorphyll content and Fe2+ content. Of the two indices of iron chlorosis, Fe2+ was more sensitive than chlorophyll content. Genotypes were grouped into efficient and inefficient categories both in terms
of absorption and utilization of iron based on the degree of reduction in response to added superphosphate. 相似文献
976.
W.B. Dandliker A.N. Hicks S.A. Levison R.J. Brawn 《Biochemical and biophysical research communications》1977,74(2):538-544
1,3,5,[10]-Estratriene-3,17β-diol-6-iminooxyacetic acid (I) and fluorescein amine condense in the presence of dicyclohexylcarbodiimide to give a fluorescent derivative of estradiol: 9{p-(1′,3′,5′[10′]-Estratriene-3′,17′β-diol-6′-iminooxyacetylamino) o-carboxyphenyl}-6-hydroxy-3-isoxanthenone (II). (II) can be prepared and isolated on a micro scale by thin layer chromatography. The results show that (II) is useful as a probe for estrogen interaction with cellular receptors and with antibody to estradiol. 相似文献
977.
Yoshio Ushijima Minoru Nakano Yasuhiro Tsuji Humio Inaba 《Biochemical and biophysical research communications》1978,82(3):853-858
The system suspended with phagocytosing leukocytes and related system produce weak light which could be greatly amplified by indole analogs with plain fatty acids at 3 position. Main emitting species in indole-3-acetic acid or indole-3-propionic acid-sensitized system was analyzed spectrometrically in the dark and ascribed to the transition of an excited indole compound in triplet state to its ground state. Such an excited species would be generated by the oxidative way of the indole analogs but not through the dioxetane structure of 2 and 3 positions on indole ring. 相似文献
978.
Hervé Geneste Karla Drescher Clarissa Jakob Loïc Laplanche Michael Ochse Maricel Torrent 《Bioorganic & medicinal chemistry letters》2019,29(3):406-412
Herein we report the discovery of a novel series of phosphodiesterase 10A inhibitors. Optimization of a HTS hit (17) resulted in potent, selective, and brain penetrant 23 and 26; both exhibited much lower clearance in vivo and decreased volume of distribution (rat PK) and have thus the potential to inhibit the PDE10A target in vivo at a lower efficacious dose than the reference compound WEB-3. 相似文献
979.
980.
Nitrite-driven nitrous oxide production under aerobic soil conditions: kinetics and biochemical controls 总被引:3,自引:0,他引:3
RODNEY T. VENTEREA 《Global Change Biology》2007,13(8):1798-1809
Nitrite (NO2−) can accumulate during nitrification in soil following fertilizer application. While the role of NO2− as a substrate regulating nitrous oxide (N2O) production is recognized, kinetic data are not available that allow for estimating N2O production or soil‐to‐atmosphere fluxes as a function of NO2− levels under aerobic conditions. The current study investigated these kinetics as influenced by soil physical and biochemical factors in soils from cultivated and uncultivated fields in Minnesota, USA. A linear response of N2O production rate () to NO2− was observed at concentrations below 60 μg N g−1 soil in both nonsterile and sterilized soils. Rate coefficients (Kp) relating to NO2− varied over two orders of magnitude and were correlated with pH, total nitrogen, and soluble and total carbon (C). Total C explained 84% of the variance in Kp across all samples. Abiotic processes accounted for 31–75% of total N2O production. Biological reduction of NO2− was enhanced as oxygen (O2) levels were decreased from above ambient to 5%, consistent with nitrifier denitrification. In contrast, nitrate (NO3−)‐reduction, and the reduction of N2O itself, were only stimulated at O2 levels below 5%. Greater temperature sensitivity was observed for biological compared with chemical N2O production. Steady‐state model simulations predict that NO2− levels often found after fertilizer applications have the potential to generate substantial N2O fluxes even at ambient O2. This potential derives in part from the production of N2O under conditions not favorable for N2O reduction, in contrast to N2O generated from NO3− reduction. These results have implications with regard to improved management to minimize agricultural N2O emissions and improved emissions assessments. 相似文献