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  • 1975-1979  (6)
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Material
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Year
  • 1
    Electronic Resource
    Electronic Resource
    EXISTENCE OF ASCORBIC ACID AS AN ACTIVATOR OF THIAMINE DlPHOSPHATASE IN RAT BRAIN (1979)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 32 (1979), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The effect of the supernatant fraction (105,000 g for 60 min) of rat brain on the microsomal thiamine diphosphatase activity was examined. The thiamine diphosphatase activity was increased by addition of the supernatant fraction. The factor activating the enzyme was a heat-stable and dialyzable substance. It caused lipid peroxidation in the microsomes and the increase of the enzyme activity was mediated through lipid peroxidation of the preparation. When the supernatant fraction was chromatographed on columns of Sephadex G-25 and Dowex 1 × 2, the activator was eluted in fractions containing ascorbic acid. The inhibitory factor of ATPase present in the supernatant fraction was also eluted with the activator. The u.v.-spectrum of the active fraction obtained by these chromatographies was the same as that of ascorbic acid. These findings indicate the existence of ascorbic acid as an activator of thiamine diphosphatase in rat brain and confirm the previous finding that the soluble factor inhibiting ATPase activity is ascorbic acid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1979.tb00369.x
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    MECHANISM OF ACTION OF NOTEXIN AND NOTECHIS 11-5 ON SYNAPTOSOMES (1978)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 31 (1978), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The neurochemical activity of notexin and notechis II-5 was investigated using a synaptosomal preparation of rat cerebral cortices. In preparations preincubated with [3H]choline in order to label acetylcholine, the toxins caused a rapid release of the transmitter which was calcium-dependent. The toxins were also potent inhibitors of high affinity choline uptake. Both agents produced a marked depolarization of the synaptosomal preparation as measured by a fluorescent dye and at high concentrations lysed the preparation. At a concentration of 0.1 μM, notexin and notechis II-5 caused a 50% increase in the efflux of lactate dehydrogenase activity. These results, together with electron microscopic observations, indicated that the toxins disrupt the synaptosomal membranes presumably by their inherent phospholipase activity. The release of acetylcholine and inhibition of choline uptake, together with the depolarization of synaptosomal membranes noted in this study, could explain the observed electrophysiological effects of these toxins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1978.tb00135.x
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    PROPERTIES OF THIAMINE DI- AND TRIPHOSPHATASES IN RAT BRAIN MICROSOMES: EFFECTS OF CHLORPROMAZINE (1975)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 24 (1975), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— The mechanism of the action of chlorpromazine on rat brain thiamine phosphatases were studied to clarify the properties of these enzymes in the CNS. Chlorpromazine at concentrations of 0.25-1.0 mm caused marked decrease of microsomal and soluble thiamine triphosphatase (TTPase) activities and marked increase of microsomal thiamine diphosphatase (TDPase) activity. Imipramine and desipramine also inhibited TTPase but did not cause any marked change in TDPase activities. Addition of chlorpromazine (0.5 mm) decreased the Vmax of microsomal TTPase by about one-half, increased that of TDPase about 3-fold, and lowered the Km value for TDP but not for TTP.Acetone treatment of the microsomal fraction lowered the TTPase activity and markedly enhanced the TDPase activity. In acetone-treated microsomes, chlorpromazine also inhibited TTPase activity but did not activate TDPase. Deoxycholate had similar effects to chlorpromazine on these enzyme activities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1975.tb03900.x
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Possible role of intestinal alkaline phosphatase activity in thiamine transport (1978)
    Springer
    Cellular and molecular life sciences 34 (1978), S. 18-20 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Thiamine deficiency caused a marked decrease of intestinal alkaline phosphatase (al-Pase) activity, but had no effect on the Ca++-ATPase activity and Ca++-absorption in rats. The al-Pase activity was significantly decreased 1 h after oral administration of ethanol at 0.5 and 2.5 g/kg. In contrast, Mg++-, Ca++- and (Na++K+)-ATPase activities did not change after the administration of ethanol. These findings show that the al-Pase activity, unlike the Ca++-ATPase activity, is not related to Ca++-absorption. A possible role of al-Pase activity in the active transport of thiamine in the intestine was discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01921875
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Thiamine diphosphatase in rat small intestine (1976)
    Springer
    Cellular and molecular life sciences 32 (1976), S. 1252-1253 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary TDPase is located mostly in the proximal portion of the small intestine and its activity, like that of ALPase, decreased markedly in thiamine deficiency. The decreased enzyme activities were restored after thiamine or vitamin D3. Kinetic and other studies of the purified enzyme indicated the identity of the two enzymes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01953076
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Possible regulation of membrane-associated cyclic AMP phosphodiesterase in rat cerebral cortex by lipids (1978)
    Springer
    Cellular and molecular life sciences 34 (1978), S. 1139-1140 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cyclic AMP phosphodiesterase (PDE) in membrane fraction from rat cerebral cortex was activated by Triton X-100, and treatment at alkaline pH and with phospholipase C. These results suggest that membrane PDE exists in a latent form and is influenced by microenvironmental changes within the membrane. Furthermore, the PDE, unlike soluble enzyme, is not influenced by a protein activator and Ca++.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01922916
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    Paper (German National Licenses)
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