Browsing by keyword "Sodium-Potassium-Exchanging ATPase"
Now showing items 1-3 of 3
-
Absence of a significant linkage between Na(+),K(+)-ATPase subunit (ATP1A3 and ATP1B3) genotypes and bipolar affective disorder in the old-order AmishPrevious studies provide evidence for a genetic component for susceptibility to bipolar affective disorder (BPAD) in the old-order Amish population. El-Mallakh and Wyatt [1995: Biol Psychiatry 37:235-244] have suggested that the Na(+),K(+)-ATPase may be a candidate gene for BPAD. This study examines the relationship between BPAD in the old-order Amish cohort and the Na(+),K(+)-ATPase alpha1 and beta3 subunit genes (ATP1A3, ATP1B3). A total of 166 sibling pairs were analyzed for linkage via nonparametric methods. Suggestive levels of statistical significance were not reached in any stratification model for affective illness. Overall, the results do not support linkage of bipolar disorder to the Na(+),K(+)-ATPase alpha subunit gene (ATP1A3) and beta subunit gene (ATP1B3) in these old-order Amish families and they show that these Na(+),K(+)-ATPase subunit genes are not major effect genes (>or=fourfold increased genetic risk of disease) for BPAD in the old-order Amish pedigrees. We cannot exclude other genetic variants of the Na(+),K(+)-ATPase hypothesis for BPAD, whereby other loci may modifying Na(+),K(+)-ATPase activity.
-
Activation of the sodium pump blocks the growth hormone-induced increase in cytosolic free calcium in rat adipocytesGH promptly increases cytosolic free calcium ([Ca2+]i) in freshly isolated rat adipocytes. Adipocytes deprived of GH for 3 h or longer are incapable of increasing [Ca2+]i in response to GH, but instead respond in an insulin-like manner. Insulin blocks the GH-induced increase in [Ca2+]i in GH-replete cells and stimulates the sodium pump (i.e. Na+/K+-ATPase), thereby hyperpolarizing the cell membrane. Blockade of the Na+/K+-ATPase with 100 microM ouabain reversed these effects of insulin and enabled GH to increase [Ca2+]i in GH-deprived adipocytes. Both insulin and GH activated the sodium pump in GH-deprived adipocytes, as indicated by increased uptake of 86Rb+. Decreasing availability of intracellular Na+ by blockade of Na+/K+/ 2Cl- symporters or Na+/H+ antiporters abolished the effects of both hormones on 86Rb+ uptake and enabled both GH and insulin to increase [Ca2+]i in GH-deprived adipocytes. The data suggest that hormonal stimulation of Na+/K+-ATPase activity interferes with activation of voltage-sensitive calcium channels by either membrane hyperpolarization or some unknown interaction between the sodium pump and calcium channels.
-
Chasing migration genes: a brain expressed sequence tag resource for summer and migratory monarch butterflies (Danaus plexippus)North American monarch butterflies (Danaus plexippus) undergo a spectacular fall migration. In contrast to summer butterflies, migrants are juvenile hormone (JH) deficient, which leads to reproductive diapause and increased longevity. Migrants also utilize time-compensated sun compass orientation to help them navigate to their overwintering grounds. Here, we describe a brain expressed sequence tag (EST) resource to identify genes involved in migratory behaviors. A brain EST library was constructed from summer and migrating butterflies. Of 9,484 unique sequences, 6068 had positive hits with the non-redundant protein database; the EST database likely represents approximately 52% of the gene-encoding potential of the monarch genome. The brain transcriptome was cataloged using Gene Ontology and compared to Drosophila. Monarch genes were well represented, including those implicated in behavior. Three genes involved in increased JH activity (allatotropin, juvenile hormone acid methyltransfersase, and takeout) were upregulated in summer butterflies, compared to migrants. The locomotion-relevant turtle gene was marginally upregulated in migrants, while the foraging and single-minded genes were not differentially regulated. Many of the genes important for the monarch circadian clock mechanism (involved in sun compass orientation) were in the EST resource, including the newly identified cryptochrome 2. The EST database also revealed a novel Na+/K+ ATPase allele predicted to be more resistant to the toxic effects of milkweed than that reported previously. Potential genetic markers were identified from 3,486 EST contigs and included 1599 double-hit single nucleotide polymorphisms (SNPs) and 98 microsatellite polymorphisms. These data provide a template of the brain transcriptome for the monarch butterfly. Our "snap-shot" analysis of the differential regulation of candidate genes between summer and migratory butterflies suggests that unbiased, comprehensive transcriptional profiling will inform the molecular basis of migration. The identified SNPs and microsatellite polymorphisms can be used as genetic markers to address questions of population and subspecies structure.
