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1.
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. 相似文献
2.
Influence of ethanol on calcium, inositol phospholipids and intracellular signalling mechanisms 总被引:1,自引:0,他引:1
Studies have implicated Ca++ in the actions of ethanol at many biochemical levels. Calcium as a major intracellular messenger in the central nervous system is involved in many processes, including protein phosphorylation enzyme activation and secretion of hormones and neurotransmitters. The control of intracellular calcium, therefore, represents a major step by which neuronal cells regulate their activities. The present review focuses on three primary areas which influence intracellular calcium levels; voltage-dependent Ca++ channels, receptor-mediated inositol phospholipid hydrolysis, and Ca++/Mg++-ATPase, the high affinity membrane Ca++ pump. Current research suggests that a subtype of the voltage-dependent Ca++ channel, the dihydropyridine-sensitive Ca++ channel, is uniquely sensitive to acute and chronic ethanol treatment. Acute exposure inhibits, while chronic ethanol exposure increases 45Ca++-influx and [3H]dihydropyridine receptor binding sites. In addition, acute and chronic exposure to ethanol inhibits, then increases Ca++/Mg++-ATPase activity in neuronal membranes. Changes in Ca++ channel and Ca++/Mg++-ATPase activity following chronic ethanol may occur as an adaptation process to increase Ca++ availability for intracellular processes. Since receptor-dependent inositol phospholipid hydrolysis is enhanced after chronic ethanol treatment, subsequent activation of protein kinase-C may also be involved in the adaptation process and may indicate increased coupling for receptor-dependent changes in Ca++/Mg++-ATPase activity. The increased sensitivity of three Ca++-dependent processes suggest that adaptation to chronic ethanol exposure may involve coupling of one or more of these processes to receptor-mediated events. 相似文献
3.
The activity of (Na+ + K+)-ATPase and acetylcholine esterase were followed in rat brain cerebral cortex, caudate, thalamus, hippocampus and medulla after i.v. administration of physostigmine. Both enzymes were found to be inhibited in a dose-dependent manner. The most pronounced inhibition of (Na+ + K+)-ATPase was found in caudate, where the highest activity of acetylcholine esterase is found. 相似文献
4.
Summary Studies have implicated Ca++ in the actions of ethanol at many biochemical levels. Calcium as a major intracellular messenger in the central nervous system is involved in many processes, including protein phosphorylation enzyme activation and secretion of hormones and neurotransmitters. The control of intracellular calcium, therefore, represents a major step by which neuronal cells regulate their activities. The present review focuses on three primary areas which influence intracellular calcium levels; voltage-dependent Ca++ channels, receptor-mediated inositol phospholipid hydrolysis, and Ca++/Mg++-ATPase, the high affinity membrane Ca++ pump.Current research suggests that a subtype of the voltage-dependent Ca++ channel, the dihydropyridine-sensitive Ca++ channel, is uniquely sensitive to acute and chronic ethanol treatment. Acute exposure inhibits, while chronic ethanol exposure increases45Ca++-influx and [3H]dihydropyridine receptor binding sites. In addition, acute and chronic exposure to ethanol inhibits, then increases Ca++/Mg++-ATPase activity in neuronal membranes. Changes in Ca++ channel and Ca++/Mg++-ATPase activity following chronic ethanol may occur as an adaptation process to increase Ca++ availability for intracellular processes. Since receptor-dependent inositol phospholipid hydrolysis is enhanced after chronic ethanol treatment, subsequent activation of protein kinase-C may also be involved in the adaptation process and may indicate increased coupling for receptor-dependent changes in Ca++/Mg++-ATPase activity.The increased sensitivity of three Ca++-dependent processes suggest that adaptation to chronic ethanol exposure may involve coupling of one or more of these processes to receptor-mediated events. 相似文献
5.
I Syrovy 《Experientia》1984,40(1):99-100
Myosin was isolated from rat ventricular myocardium, and its properties were compared in adult and very old animals. Ca2+ -ATPase activity of ventricular myosin was found to be lower in very old animals as compared with adult ones; K+ -ATPase activity, however, does not change with the aging process. Neither were there any differences between the two age groups in the pattern of ventricular light chains of myosin. 相似文献
6.
M Zanca M Cayzac J Philippot 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1976,283(16):1795-1798
The (Na+-K+)-ATPase in plasma membrane from Mammiferous endometrium is characterized by the Mg/ATP ratio equal to one, and by a distinct affinity for Na+ (1.3 mM) and K+ (2 mM). The activity is maximum for pH 7.4-7.5 in presence of Mg++ 2mM and ATP 2 mM, Na+ 140 mM and K+ 10 mM. 相似文献
7.
D Charlemagne J Léger K Schwartz B Geny A Zachowski L Lelièvre 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1979,288(11):963-966
EDTA treatment of isolated plasma membranes from MF2S cells increased 1,000 fold the sensitivity of (Na+ + K+) ATPase activity to ouabain. The original sensitivity of the enzyme to the drug is recovered after addition of tropomyosin together with Ca++ ions to the treated membranes. 相似文献
8.
Na +, K + -adenosinetriphosphatase (Na +, K + -ATPase) activity was decreased in liver plasma membranes from rats in which cholestasis had been induced by i.v. administration of sodium taurolithocholate (5 mumoles/100 g b. wt). Incubation of liver plasma membranes with taurolithocholate (10--1300 muM) caused significant and dose dependent reductions of Na +, K + -ATPase activity at taurolithocholate concentrations above 100 muM. These findings lend support to the hypothesis that cholestasis induced by monohydroxy bile acids is at least partially the result of an inhibition of hepatic Na +, K + -ATPase activity. 相似文献
9.
Oscillatory after-potentials and triggered-automaticity were observed in dog ventricular muscle fibres when the fibres were exposed to K+-free,high-Ca++-solutions after K+-free,Ca++-free perfusion. They appeared at membrane potentials more negative than--60 m V. 相似文献
10.
The (Na+ 4 K+)- and Mg2+-dependent ATPase distribution in several brain areas has been investigated in Quaking mutant mice characterized by myelin deficiency. A marked decrease of (Na+ + K+)-ATPase activity has been found in limbic structures, hypothalamus and cerebellum. The Mg2+-dependent activity did not change. A possible involvement of the impairment of the (Na+ + K+)-ATPase activity in the seizure susceptibility of this mice is discussed. 相似文献
11.
C J Duncan 《Experientia》1977,33(7):923-924
It is suggested that ouabain promotes catecholamine release by causing a rise in intracellular Na+ which, in turn, causes an elevated steady-state level of intracellular Ca2+. It is suggested that the Na+-K+-ATPase is not directly involved in exocytosis at either adrenergic or cholinergic synapses. 相似文献
12.
R Ochi 《Experientia》1975,31(9):1048-1049
The membrane potential in guinea-pig's papillary muscles from right ventricle was recorded by glass microelectrodes and stimulation was effected by current pulses applied through a sucrose-gap. Action potentials with overshoot were recorded in the solution lacking Na+ and Ca++ but containing 2-95 mM Mn++. The overshoot was increased with the increase of [Mn++]o by about 30 mV/decade. Similar Mn++ dependent action potentials were also obtained in Na-free solution containing 0.6 mM Ca++. The results indicate that Mn inward current is sufficient to generate action potentials in cardiac muscle. 相似文献
13.
Vinblastine selectively inhibits the activation of brain cyclic AMP phosphodiesterase activity by Ca++-protein activator (50% inhibition by 2 x 10(-5) M). This inhibitory effect was reversed by excessive amounts of the activator, whereas large quantities of Ca++ caused only a slight suppression of the vinblastine effect. This result of vinblastine suggests a new site of its action and also suggests the possible role of protein activator, phosphodiesterase proteins or cyclic nucleotides in the previously known effects of vinblastine in vivo and in vitro. 相似文献
14.
L Lelièvre D Charlemagne A Paraf 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1976,283(5):539-542
Purified plasma membranes from a cell line derived from the murine plasmocytoma MOPC 173 exhibited a 50% inhibition of the Na+K+ ATPase by 120 muM ouabain. EDTA treatment of such membranes induced a drop in the ouabain concentration needed for 50% inhibition to 0.4 muM. Supernatants obtained after EDTA treatment were able to complement with Ca(++) + Mg++ the washed EDTA treated membranes which recover their original resistance. 相似文献
15.
Under certain conditions, taurine (3.0mM) potentiated cardiac contractile response to ouabain in the normal medium. The potentiation by taurine was also observed in the low K+ medium, in which the positive inotropic effect of ouabain increased. The potentiation as seen in both media was, at least in part, due to the increase by taurine of Ca++ content in the heart. Taurine in the heart was not directly related to this potentiation. 相似文献
16.
Release of Ca++, Mg++ and K+ by the carboxylic ionophore X-14547 A was studied in the mitochondrial membrane. A comparison was made with A.23187 ( Calcimycin ) and X.537 A (Lasalocid A) under the same experimental conditions. It was shown that in this test system X.14547 A is primarily a K+ carrier comparable with X.537 A. 相似文献
17.
T. Stojanovié B. M. Djuričić B. B. Mršulja 《Cellular and molecular life sciences : CMLS》1980,36(12):1348-1350
Summary The activity of (Na++K+)-ATPase and acetylcholine esterase were folloed in rat brain cerebral cortex, caudate, thalamus, hippocampus and medulla after i.v. administration of physostigmine. Both enzymes were found to be inhibited in a dose-dependent manner. The most pronounced inhibition of (Na++K+)-ATPase was found in caudate. where the highest activity of acetylcholine esterase is found.These studies were supported by a grant from the Union of Science of Republic Serbia, No. 40404-14. 相似文献
18.
With a suitable modification of the Farquhar and Palade technique the Na+ + K+-ATPase activity in guinea-pig thyroid is demonstrated. The addition of c-AMP (5 X 10(-6) M or 1.5 X 10(-5) M) to the incubation media produced an apparent intensification of the Na+ + K+ -ATPase activity in the thyroid. 相似文献
19.
Brook trout (Salvelinus fontinalis, Mitchill) were acclimated over 15 weeks to either +4 degrees C or +24 degrees C. The effects of temperature on myofibrillar Mg2+Ca2+-ATPase activities were investigated. In contrast to goldfish, temperature acclimation does not alter the kinetic properties of the brook trout myofibrillar ATPase. Activation energy (delta G not equal to) is lower and substrate turnover number is higher than values previously reported for cold-adapted stenotherms. Properties of brook trout ATPase appear to be a compromise enabling function across a broad temperature range. The different strategies of adapting to seasonal temperature variations are briefly discussed. 相似文献
20.
R Barbier M Pitiot L Colobert 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1975,280(14):1737-1740
In earlier reports we have shown the existence in human lymphocytes homogenate, of a cyclic-AMP dependent protein-kinase activity. We demonstrate by affinity chromatography that two subunits display respectively cyclic-AMP binding and phosphorylating properties. Divalent cations such as Ca++, Mg++ or Mn++ are required for enzymatic activity. ATP which is an obligatory cosubstrate acts as an inhibitor when its concentration is higher than 10(-6)M. 相似文献