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1.
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.
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
3.
H. Dransfeld K. Greeff D. Hess A. Schorn 《Cellular and molecular life sciences : CMLS》1967,23(5):375-377
Summary In isolated mitochondria of heart muscle from rabbits and oxen there is, under suitable conditions, an accumulation of Ca++, which is significantly enhanced by elevating the K+/Na+ quotient of the incubation medium. K-strophanthine (10–5–10–7) does not influence the accumulation of Ca++ by the mitochondria of heart muscle. Therefore the intracellular increase in exchangeable Ca++ observed after digitalis-glycosides could be explained by a decrease of the intracellular K+/Na+ quotient, which is caused by inhibition of the membrane ATPase and diminishes the capacity for Ca++ accumulation in mitochondria. 相似文献
4.
S. J. Blumenthal M. M. McConnaughey S. G. Iams 《Cellular and molecular life sciences : CMLS》1982,38(6):707-709
Summary Myocardial isoproterenol-stimulated adenylate cyclase, Na+, K+-ATPase and K+, Ca++-ATPase activities are elevated in the spontaneously hypertensive rat and can be lowered by methimazole-induced hypothyroidism which also prevents the development of hypertension. Although thyroid hormone levels are similar between untreated SHRs and WKY rats, the thyroid is apparently necessary for the expression of spontaneous hypertension.Acknowledgments. Supported by North Carolina Heart Grant No. 40301 and a grant from Sigma Xi. 相似文献
5.
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
6.
G. Matthes H. A. Hackensellner A. Hartwig 《Cellular and molecular life sciences : CMLS》1978,34(8):1024-1025
Summary The influence of electrolyte composition and glucose concentration of a cryprotective medium on the survival of auricle fragments from adult rat hearts after storage at –196°C was investigated. Using a K+-, Mg++-, Ca++-rich solution with increased glucose concentration, a high rate of surviving fragments was found after cryopreservation. 相似文献
7.
Summary 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 mV. 相似文献
8.
M. -P. Sauviat J. -M. Chesnais J. Diacono J. -F. Biard J. -F. Verbist 《Cellular and molecular life sciences : CMLS》1994,50(10):926-930
Bistramide A, a new toxin isolated from the UrochordateLissoclinum bistratum Sluiter, was applied to rat auricular heart muscle bundles. At a stimulation frequency of 0.2 Hz, the toxin induces a dose-dependent reduction of the stimulated twitch tension force; it decreases
and shortens the duration of the plateau and the slow repolarizing phase of the action potential. In the control solution, switching from a stimulation frequency of 0.2 Hz to 1 Hz decreases the force with which a positive potentiation develops either at a maintained high frequency or after switching from 1 Hz to 0.2 Hz. Bistramide A reduces both the force evoked at 1 Hz and the potentiation. The data suggest that Bistramide A blocks Na+ conductance; inhibits Ca++ channels in a time-and frequency-dependent manner; reduces Na+–Ca++ exchange activity; but does not modify the ability of the sarcoplasmic reticulum to be refilled although the rate of Ca++ accumulation is decreased. 相似文献
9.
Summary 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
10.
M. Kohlhardt B. Bauer H. Krause A. Fleckenstein 《Cellular and molecular life sciences : CMLS》1972,28(3):288-289
Zusammenfassung Die Ca++-Leitfähigkeit der Myokardfaser-Membran wird durch Verapamil und sein Methoxyderivat D 600 teilweise bis zum vollständigen Verlust reduziert. Dieser Effekt erfolgt selektiv, da die Na+-Leitfähigkeit der Membran unbeeinflusst bleibt. Die während der Erregung der Myokardfaser fliessenden transmembranären Ca++- und Na+-Ströme benutzen demzufolge voneinander unabhängige Membrankanäle. 相似文献
11.
Summary The cytoplasma fraction of the bovine choroid plexus epithelial cells was found to contain a considerable ATPase activity. The influence of Na+, K+, Li+, Rb+, Cs+, Co++, Mn++, Zn++ and Fe+++ on the activity of the Mg++-dependent enzyme has been studied. The monovalent cations do not influence the enzymic activity, whereas the effect of the bi- and trivalent cations is characterized by an inhibition of the ATPase. 相似文献
12.
Summary Respiratory ionic content (Na+, K+, Ca++) of hepatic tissue and ionic excretion measurements were performed in the TenchTinea tinea kept in diluted sea water. After bilateral section of parasympathetic system, the changes of Na/K value are less than in fresh water. The survival and hepatic O2 uptake were the same. It is suggested than after both vagi section sea water Ca++ allowed a best osmoregulation in this species.
Ce travail a été réalisé avec la collaboration technique de A.Rup. 相似文献
Ce travail a été réalisé avec la collaboration technique de A.Rup. 相似文献
13.
Résumé L'augmentation de la concentration en potassium (K+) à 25 meq/l et au delà, du liquide dans lequel des hypophyses de rat sont incubées in vitro stimule la sécrétion de l'hormone thyréotrope (TSH). La présence de l'ion calcium (Ca++) est nécessaire à cet effet de K+; l'incubation dans un milieu sans Ca++ empèche l'effet (sécrétion de TSH) de K+, qui est rétabli quand on réintroduit Ca++ dans le liquide d'incubation. La stimulation de la sécrétion de TSH due à K+ est inhibée par la thyroxine. Les effets de K+ sur la sécrétion de TSH sont identiques à ceux de TRF (TSH-releasing factor) hypothalamique, en ce qui concerne la présence de Ca++ et l'inhibition par la thyroxine.
Supported by USPHS research grants Nos. AM 08290.04, HD 02577.01, training grant No. GM 956.04; also No. FR 00254 to Common Research Computer Facility, Texas Medical Center. We are pleased to acknowledge the excellent assistance of Mrs.Nancy Pace in the assays involved here. 相似文献
Supported by USPHS research grants Nos. AM 08290.04, HD 02577.01, training grant No. GM 956.04; also No. FR 00254 to Common Research Computer Facility, Texas Medical Center. We are pleased to acknowledge the excellent assistance of Mrs.Nancy Pace in the assays involved here. 相似文献
14.
F. Reusser 《Cellular and molecular life sciences : CMLS》1966,22(5):309-310
Zusammenfassung Hochgereinigtes Rinderwachstumshormon besitzt ein ziemlich gutes Bindungsvermögen für Mg++-, Ca++- und Na+-Ionen. Andererseits wird K+ je nach Konzentration überhaupt nicht, oder nur in Spuren gebunden.
The performance of the elementary analyses by R. C.Anderson is gratefully acknowledged. Thanks are also due to B.Czuk and N. O.Milkovich for technical assistance. 相似文献
The performance of the elementary analyses by R. C.Anderson is gratefully acknowledged. Thanks are also due to B.Czuk and N. O.Milkovich for technical assistance. 相似文献
15.
Summary The biological effects of lithium ions have been studied, using plant cytokinesis in onion root meristems as the experimental model. Lithium induces binucleate cells by inhibiting cell plate formation. Moreover, lithium and caffeine have additive effects on the induction of binucleate cells. Na+, K+, Ca++ and Mg++ antagonize lithium-induced inhibition of cytokinesis. 相似文献
16.
P. Mandel V. Stefanovic J. C. Hermetet A. Ebel 《Cellular and molecular life sciences : CMLS》1976,32(1):77-79
Summary The (Na++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.Chargée de Recherche au CNRS. 相似文献
17.
Sampaio MS Bezerra IP Peçanha FL Fonseca PH Capella MA Lopes AG 《Cellular and molecular life sciences : CMLS》2008,65(19):3093-3099
The lack of Na+,K+-ATPase expression in intercalated cells (IC) is an intriguing condition due to its fundamental role in cellular homeostasis.
In order to better understand this question we compared the activities of Na+,K+-ATPase and Na+-ATPase in two MDCK cell clones: the C11, with IC characteristics, and the C7, with principal cells (PC) characteristics.
The Na+,K+-ATPase activity found in C11 cells is far lower than in C7 cells and the expression of its β-subunit is similar in both cells.
On the other hand, a subset of C11 without α-subunit expression has been found. In C11 cells the Na+-ATPase activity is higher than that of the Na+,K+-ATPase, and it is increased by medium alkalinization, suggesting that it could account for the cellular Na+-homeostasis. Although further studies are necessary for a better understanding of these findings, the presence of Na+-ATPase may explain the adequate survival of cells that lack Na+,K+-ATPase.
Received 09 July 2008; received after revision 03 August 2008; accepted 12 August 2008 相似文献
18.
Dhar-Chowdhury P Malester B Rajacic P Coetzee WA 《Cellular and molecular life sciences : CMLS》2007,64(23):3069-3083
Glycolysis is an evolutionary conserved metabolic pathway that provides small amounts of energy in the form of ATP when compared
to other pathways such as oxidative phosphorylation or fatty acid oxidation. The ATP levels inside metabolically active cells
are not constant and the local ATP level will depend on the site of production as well as the respective rates of ATP production,
diffusion and consumption. Membrane ion transporters (pumps, exchangers and channels) are located at sites distal to the major
sources of ATP formation (the mitochondria). We review evidence that the glycolytic complex is associated with membranes;
both at the plasmalemma and with membranes of the endo/sarcoplasmic reticular network. We examine the evidence for the concept
that many of the ion transporters are regulated preferentially by the glycolytic process. These include the Na+/K+-ATPase, the H+-ATPase, various types of Ca2+-ATPases, the Na+/H+ exchanger, the ATP-sensitive K+ channel, cation channels, Na+ channels, Ca2+ channels and other channels involved in intracellular Ca2+ homeostasis. Regulation of these pumps, exchangers and ion channels by the glycolytic process has important consequences
in a variety of physiological and pathophysiological processes, and a better understanding of this mode of regulation may
have important consequences for developing future strategies in combating disease and developing novel therapeutic approaches.
Received 20 July 2007; received after revision 30 July 2007; accepted 17 August 2007 相似文献
19.
Summary Free and masked SH groups were determined in haptoglobine (Hp) haemoglobine (Hb) (horse) and in their complex (Hb-Hp). Hp contains no free SH groups, but up to 9 groups are liberated per mol on denaturation by guanidine. The Hb-Hp complex reacts with the same number of Hg++ ions as free Hb, but it reacts with one less Ag+ ion than free Hb. The 4th Ag+ ion is taken up only in the presence of low concentration of a denaturing agent. Hg++, Ag+, Cu++ pcmb and iodine do not inhibit the association of Hb and Hp nor do they diminish the peroxidasic activity of the complex. Sh groups of Hb do not seem to be involved in these two reactions. 相似文献
20.
M. Sakon T. Tsujinaka J. Kambayashi G. Kōsaki 《Cellular and molecular life sciences : CMLS》1982,38(9):1099-1101
Summary An endogenous, specific inhibitor of high molecular weight has been isolated from bovine blood platelets, which inhibits the activity of the 2 forms of platelet Ca++ activated neutral proteases reported previously by us. The inhibition is not due to chelation of Ca++ but results from a stoichiometric complex formation. 相似文献