Effect of sex and localization dependent differences of Na,K-ATPase properties in brain of rat (original) (raw)
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Molecular cloning of rat brain Na,K-ATPase alpha-subunit cDNA
Proceedings of the National Academy of Sciences, 1985
We have isolated a cDNA clone for the rat brain Na,K-ATPase a subunit. A Agtll cDNA expression library constructed from mRNA of 1-and 2-week-old rat brains was screened with an antibody reactive with rat brain Na,K-ATPase. A positive phage clone, ArbS, containing a 1200-basepair cDNA insert expressed a fi-galactosidase-cDNA fusion protein that was reactive by immunoblotting with the Na,K-ATPase antibody. This fusion protein was also reactive in ELISA with a monoclonal antibody directed against the a subunit of the Na,K-ATPase. A 27S mRNA species exhibiting sequence hybridization to the cDNA insert of Xrb5 was identified in rat brain, kidney, and liver, as well as in dog kidney. This 27S mRNA exhibited a tissue-specific pattern of abundance consistent with the relative abundance of Na,K-ATPase polypeptides in vivo: kidney > brain > liver. In a ouabainresistant HeLa cell line, C+, which contains minute chromosomes and at least a 10-fold greater number of sodium pumps
Effect of duration of diabetes mellitus type 1 on properties of Na, K-ATPase in cerebral cortex
Molecular and Cellular Biochemistry, 2015
Time sequence study was performed to characterize the effects of diabetes mellitus type 1 on properties of the Na, K-ATPase in cerebral cortex derived from normal and streptozotocin (STZ)-diabetic rats of both genders. The samples were excised at varying time intervals of diabetes induced by STZ (65 mg kg-1) for 8 days, and 8 and 16 weeks. Expression of a1-3 isoforms of Na, K-ATPase was not altered in statistically significant level during all stages of diabetes neither in female nor in male rats as revealed from Western blot analysis. Studies of kinetic properties of the enzyme resulted in variations in active number of Na, K-ATPase molecules as well as its qualitative properties. Sixteen-week-old control male rats showed better affinity to substrate as indicated by 13 % decrease of K m value. The effect persisted also in males subjected to 8 days lasting diabetes; however, in males subjected to 8 weeks lasting diabetes, the effect was lost. In 25-week-old rats, the Na, K-ATPase revealed again altered properties in males and females but the mechanism of the variation was different. In females, the number of active molecules of Na, K-ATPase was higher by 32 % in controls and by 17 % in rats with chronic diabetes when comparing to respective male groups as suggested by increased value of V max. So the properties of Na, K-ATPase in cerebral cortex, playing crucial role in maintaining intracellular homeostasis of Na ? ions, depend on gender, age, and duration of diabetic insult.
General physiology and biophysics, 1997
The activities and basic enzymatic properties of Na,K-ATPase were examined in synaptosomal plasma membranes (SPM) prepared from rat hippocampus and striatum. A kinetic analysis showed profound differences in apparent affinities for ATP (Km) between hippocampal (1.21 mmol/l) and striatal (0.76 mmol/l) enzyme preparations, as well as in the corresponding Vmax values. However, physiological efficiencies were almost the same. The complex pattern of dose-response curves to ouabain indicated the presence of two high-affinity forms of Na,K-ATPase in the striatum ("very high-": Ki = 3.73 x 10(-8) mol/l and "high-": Ki = 4.21 x 10(-5) mol/l), and one high affinity form in the hippocampus (Ki = 6.6 x 10(-7) mol/l). In addition, both SPM preparations contained one low affinity form with similar Ki. The "very high-affinity" form had positive cooperativity for ouabain inhibition of Na,K-ATPase activity, in contrast to "high" and "low-affinity" fo...
Biochimica et Biophysica Acta (BBA) - Biomembranes, 1995
In this study we analysed the changes in the properties of rat cerebral cortex Na+/K+-ATPase in streptozotocin induced diabetes (STZ-diabetes). Special attempt was made to determine whether insulin treatment of diabetic animals could restore the altered parameters of this enzyme. Na+/K+-ATPase activity was found to be decreased by 15% after 2 weeks, and by 37% after 4 weeks in diabetic rat brains with a parallel decrease in maximal capacity of low affinity ouabain binding sites. There was no significant change in the high affinity ouabain binding sites. The K d values did not change significantly. Western blot analysis of brain Na+/K---ATPase isoforms indicated a 61 +_ 5.8% and 20 +_ 2,8% decrease of the a~ and 0/3 isoforms, respectively in 4 weeks diabetic animals. Change in the amount of the a 2 isoform proved to be less characteristic. Both types of/3 subunit isoform showed a significant decrease in four weeks diabetic rats. Our data indicate a good correlation in diabetic rats between changes in Na+/K+-ATPase activity, low affinity ouabain binding capacity and the level of a~ isoforrn. While insulin treatment of diabetic animals restored the blood glucose level to normal, a complete reversal of diabetes induced changes in Na+/K+-ATPase activity, ouabain binding capacity and Na+/K+-ATPase isoform composition could not be achieved,
Proceedings of the National Academy of Sciences, 1991
We have used in situ hybridization histochemistry to analyze the subceilular distribution of mRNAs encoding Na,K-ATPase a-and /3-subunit isoforms in the rat central nervous system. Substantial differences in the cellspecific pattern ofexpression were found for the genes encoding three isoforms of the a subunit. Transcripts of al-subunit gene were detected in virtually all cell types and structures examined. Expression of a2-subunit mRNA was characteristic of glia, whereas a3-subunit transcripts were predominant in neurons. Transcripts encoding the /31 subunit were detected in neurons, whereas /32-subunit mRNA expression was characteristic of glia. mRNA encoding both /3-subunit isoforms was present in choroidal epithelial cells. The distribution pattern of a-and /8-subunit mRNAs in structures throughout the central nervous system is consistent with the possibility of six structurally distinct Na',K+-ATPase isoenzymes.