Effects of Na+ depletion on fluid secretion and levels of phosphorus compounds as measured by 31P-NMR in perfused canine mandibular gland.
The dependency of fluid secretion on extracellular Na+ and the levels of phosphorus compounds were studied in the perfused canine mandibular gland (using 31P-NMR). During control perfusion, the resting levels of creatine phosphate (CP) and ATP were 0.62 +/- 0.05 mmol . kg-1 gland and 0.42 +/- 0.04 mmol . kg-1 (mean +/- S.E., n = 9), respectively. Acetylcholine (Ach; 1 mumol . l-1 for 3 min) induced a salivary secretion and decreased the CP level. When Na+ in the perfusate was completely replaced with Li+, Ach induced only a minimal salivary secretion and no change in the ATP and CP levels. Restitution of Na+ to the perfusion, even without added Ach, caused a decrease in ATP and CP, and a small increase in salivary secretion. These results suggest that the activity of Na+/K+ ATPase is increased inversely via a rise of the intracellular Na+ concentration and that the salivary secretion is induced not only by added secretagogues but by an increase in the Na+ entry without added secretagogues.
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001826:Body Fluids / Q000378:metabolism*; D004285:Dogs; D009682:Magnetic Resonance Spectroscopy; D010477:Perfusion; D010725:Phosphocreatine / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism*; D012964:Sodium / Q000172:deficiency*; D013363:Submandibular Gland / Q000378:metabolism*
D010725:Phosphocreatine; D010758:Phosphorus; D000255:Adenosine Triphosphate; D012964:Sodium