Abstract
To investigate the functional role of the different Na+, K(+)-ATPase alpha (catalytic) subunit isoforms in neuronal cells, we used quantitative in situ hybridization with riboprobes specific for alpha 1, alpha 2, and alpha 3 isoforms to measure the level of alpha isoform-specific expression in the neuroendocrine cells of the supraoptic (SON) and paraventricular (PVN) nuclei of rat hypothalamus. A prolonged increase in electrical activity of these cells, achieved by 5 days of salt treatment, increased the amount of alpha 1 isoform mRNA in the SON and PVN by 50%. Levels of alpha 1 mRNA in other brain regions and levels of alpha 2 and alpha 3 mRNAs were not affected by salt treatment. We conclude that the alpha 1 isoform Na+, K(+)-ATPase may be specifically adapted to pump out Na+, which enters the cells through voltage-gated channels during neuronal depolarization.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Enzyme Activation / physiology
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Gene Expression Regulation, Enzymologic / physiology*
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Ion Channel Gating / drug effects
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Ion Channel Gating / physiology
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Isoenzymes / genetics*
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Isoenzymes / physiology
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Male
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Paraventricular Hypothalamic Nucleus / chemistry
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Paraventricular Hypothalamic Nucleus / enzymology
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RNA, Messenger / analysis
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RNA, Messenger / genetics*
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Rats
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Rats, Inbred Strains
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Sodium / pharmacology
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Sodium Channels / drug effects
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Sodium Channels / physiology
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Sodium-Potassium-Exchanging ATPase / genetics*
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Sodium-Potassium-Exchanging ATPase / physiology
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Supraoptic Nucleus / chemistry
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Supraoptic Nucleus / enzymology
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Synaptic Transmission / physiology
Substances
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Isoenzymes
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RNA, Messenger
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Sodium Channels
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Sodium
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Sodium-Potassium-Exchanging ATPase