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NA
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I. (noun)
Sense 1
Meaning:
A silvery soft waxy metallic element of the alkali metal group; occurs abundantly in natural compounds (especially in salt water); burns with a yellow flame and reacts violently in water; occurs in sea water and in the mineral halite (rock salt)
Synonyms:
atomic number 11; Na; sodium
Classified under:
Hypernyms ("Na" is a kind of...):
metal; metallic element (any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.)
Holonyms ("Na" is a substance of...):
halite; rock salt (naturally occurring crystalline sodium chloride)
brine; saltwater; seawater (water containing salts)
Context examples:
Lidocaine interacts with voltage-gated Na+ channels in the nerve cell membrane and blocks the transient increase in permeability of excitable membranes to Na+.
(Lidocaine Hydrochloride, NCI Thesaurus)
Through the homeostasis mechanism in balancing total ion concentration (Ca++, Na+), it reduces vascular hyperreactivity and peripheral and arterial vascular resistance, possibly by inhibiting transmembrane ionic influx, probably calcium ions, and stimulating prostaglandin E2 synthesis, thereby causing vasodilatation.
(Indapamide, NCI Thesaurus)
Loop diuretics block and inhibit the function of the sodium-potassium-chloride (Na+, K+, Cl-) cotransporter system in the thick ascending limb of the loop of Henle, thereby inhibiting the reabsorption of sodium, potassium, and chloride ions.
(Loop Diuretic, NCI Thesaurus)
Lithium interferes with transmembrane sodium exchange in nerve cells by affecting sodium, potassium-stimulated adenosine triphosphatase (Na+, K+-ATPase); alters the release of neurotransmitters; affects cyclic adenosine monophosphate (cAMP) concentrations; and blocks inositol metabolism resulting in depletion of cellular inositol and inhibition of phospholipase C-mediated signal transduction.
(Lithium Carbonate, NCI Thesaurus)
In addition, this agent exerts its mineralocorticoid effect on the distal tubules and collecting ducts of the kidney by inducing permease, an enzyme that regulates Na+ permeability in cells, thereby enhancing Na+ reabsorption and water retention as well as increasing K+, H+ excretion.
(Fludrocortisone, NCI Thesaurus)
Although the mechanism of action of bufogenin is still under investigation, this agent is a specific Na+/K+-ATPase inhibitor and has been shown to reduce blood pressure in a rat model of preeclampsia.
(Bufogenin, NCI Thesaurus)
"Na! Na!" the men cried.
(Love of Life and Other Stories, by Jack London)
Odorant molecules bind to a receptor protein (R) coupled to an olfactory specific Gs-protein (G) and activate a type III adenylyl cyclase (AC), increasing intracellular cAMP levels. cAMP targets an olfactory-specific cyclic-nucleotide gated ion channel (CNG), allowing cations, particularly Na and Ca, to flow down their electrochemical gradients into the cell, depolarizing the ORN.
(Olfactory Transduction Pathway, NCI Thesaurus/KEGG)
Recovery occurs as Ca2+ is pumped out of the cell by the Na+/Ca2+ exchanger (NCX) or is returned to the sarcoplasmic reticulum (SR) by sarco(endo)plasmic Ca2+ -ATPase (SERCA) pumps on the non-junctional region of the SR.
(Cardiac Muscle Contraction Pathway, NCI Thesaurus/KEGG)
Although the mechanism of action of bufalin is still under investigation, this agent is a specific Na+/K+-ATPase inhibitor and can induce apoptosis in cancer cell lines through the activation of the transcription factor AP-1 via a mitogen activated protein kinase (MAPK) pathway.
(Bufalin, NCI Thesaurus)
