title: Continuous measurements of Na, Li, and Cl in the perfused salivary gland by use of NMR.
abstract: The present study was undertaken to measure tissue contents of Na, Li, and Cl non-invasively in the isolated perfused organ by nuclear magnetic resonance (NMR) using a broadband tunable probe. The NMR signals of 23Na, 7Li, and 35Cl from the isolated perfused rat mandibular gland were collected continuously and each spectrum was obtained for every 15 or 20 s. The Na concentration in the perfusate was varied by replacement with Li, and the resulting changes were monitored by measuring the signal intensities of the electrolytes. The time constant for Na exchange was slower following complete removal of extracellular Na than following its half replacement, suggesting that the Na extrusion by Na+/K+ ATPase was reduced by lowering the extracellular Na level. The time constant for Li exchange was slower than that for Na exchange. The level of Cl was nearly constant during experiment, except for a very slow increase in Cl, possibly resulting from increasing edema and/or intracellular Li storage.
mesh_terms: D000818:Animals; D002712:Chlorides / Q000378:metabolism*; D008094:Lithium / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D010477:Perfusion; D051381:Rats; D012463:Saliva / Q000378:metabolism; D012469:Salivary Glands / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D013997:Time Factors
chemical_list: D002712:Chlorides; D008094:Lithium; D012964:Sodium