Summary
1. Using micropuncture and microcatheterization techniques, samples of fluid were collected from the intercalated ducts, lobar ducts, upper main duct and lower main duct of the rat submaxillary gland, and analyzed for Na, K, and osmolality.
2. Intercalated duct fluid was isotonic, with plasma-like concentrations of both Na and K. The composition of this fluid was unaltered by stimulation of the gland with parasympathomimetic drugs.
3. Lobar duct fluid was nearly isotonic at unstimulated salivary flow rates, but became profoundly hypotonic (114 mOsm/kg) following gland stimulation. Concentration of Na fell from 70–140 mEq/l, in the resting state, to less than 5 mEq/l, after stimulation. Under conditions of maximal stimulation the Na concentration rose slightly to about 40 mEq/l. Concentrations of K were plasma-like at the lowest flow rates, rose to more than 100 mEq/l at flow rates of 1 μl/g min, and then fell to approach a constant value of 32 mEq/l at flow rates in excess of 20 μl/g min. These data suggested that the primary saliva, produced in the acinar-intercalated duct region of the gland, was modified during its passage along the sublobular ducts by processes of Na reabsorption in excess of water, and of K secretion. At low flow rates this modified fluid was thought to have been able to re-equilibrate with plasma distal to the site of sodium and potassium transport; at high rates of secretion this re-equilibration was thought not to occur to any appreciable extent.
4. Samples collected from the main duct showed falls in osmolality and Na concentration, and a rise in K concentration, along the length of the duct. Although demonstrable under stimulated conditions, the action of the main duct on salivary Na and K concentrations only assumed significant proportions at low flow rates; then it was able to reduce Na concentration to less than 5 mEq/l, and to increase K to more than 130 mEq/I. This second locus of electrolyte transport, in the submaxillary main duct, does not seem to be present in the other rat salivary glands.
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References
Brusilow, S. W., and R. E. Cooke: Role of parotid ducts in secretion of hypotonic saliva. Amer. J. Physiol. 196, 831–834 (1959).
Burgen, A. S. V.: The secretion of potassium in saliva. J. Physiol. (Lond.) 132, 20–39 (1956).
Burgen, A. S. V., and N. G. Emmelin: Physiology of the salivary glands. London: Edward Arnold (Publishers) Ltd. 1961.
— K. G. Terroux, and E. Gonder: The sites of transfer of sodium, potassium, and iodide in the parotid duct system of the dog. Canad. J. Biochem. 37, 359–370 (1959).
Emrich, H. M., and K. J. Ullrich: Ausscheidung verschiedener Stoffe im Schweiß in Abhängigkeit von der Schweißflußrate. Pflügers Arch. ges. Physiol. 289, 83 R (1966).
Graham, A. R., and G. W. Stavraky: Reversal of the effects of chorda tympani stimulation, and of acetylcholine and adrenaline, as seen in the submaxillary salivary gland of the cat. Rev. Canad. Biol. 11, 446–470 (1953).
Henriques, B. L.: Acinar-duct transport sites for Na+ and K+ in dog submaxillary gland. Amer. J. Physiol. 201, 935–938 (1961).
— A technique of studying salivary gland function. Amer. J. Physiol. 203, 1086–1090 (1962).
Holzgreve, H., J. R. Martinez, and A. Vogel: Micropuncture and histologic study of submaxillary glands of young rats. Pflügers Arch. ges. Physiol. 290, 134–143 (1966).
Jacoby, F., and C. R. Leeson: The post-natal development of the rat submaxillary gland. J. Anat. (Lond.) 93, 201–216 (1959).
Langley, L. L., and R. S. Brown: Relationship of salivary flow and pressure in dog submaxillary and parotid gland. Amer. J. Physiol. 201, 285–286 (1961).
— C. H. Gunthorpe, and W. A. Beall: Parotid clearance of sodium and potassium. Amer. J. Physiol. 195, 693–696 (1958).
Langstroth, G. O., D. R. McRae, and G. W. Stavraky: The secretion of protein material in the parasympathetic submaxillary saliva. Proc. roy. Soc. B 125, 335–347 (1938).
Ludwig, C.: Neue Versuche über die Beihilfe der Nerven zur Speichelabsonderung. Z. rat. Med. 1, 255–277 (1851).
Lundberg, A.: Electrophysiology of salivary glands. Physiol. Rev. 38, 21–40 (1958).
Malnic, G., R. M. Klose, and G. Giebisch: Micropuncture study of renal potassium excretion in the rat. Amer. J. Physiol. 206, 674–686 (1964).
Mangos, J. A., and G. Braun: Excretion of total solute, sodium, and potassium in the saliva of the rat parotid gland. Pflügers Arch. ges. Physiol. 290, 184–192 (1966).
—— and K. F. Hamann: Micropuncture study of sodium and potassium excretion in the rat parotid saliva. Pflügers Arch. ges. Physiol. 291, 99–106 (1966).
Marsh, D. J., K. J. Ullrich, and G. Rumrich: Micropuncture analysis of the behavior of potassium ions in rat renal cortical tubules. Pflügers Arch. ges. Physiol. 277, 107–119 (1963).
Martinez, J. R., H. Holzgreve, and A. Frick: Micropuncture study of submaxillary glands of adult rats. Pflügers Arch. ges. Physiol. 290, 124–133 (1966).
Ramsay, J. A., and R. H. J. Brown: Simplified apparatus and procedure for freezing point determination upon small volumes of fluid. J. sci. Instrum. 32, 372–375 (1955).
Schneyer, C. A., and L. H. Schneyer: Electrolyte levels of rat salivary secretions. Proc. Soc. exp. Biol. (N.Y.) 101, 568–569 (1959).
——: Secretion by salivary glands deficient in acini. Amer. J. Physiol. 201, 939–942 (1961).
Schögel, E., and J. A. Young: Micropuncture and perfusion investigation of sodium and potassium transport in the rat submaxillary gland. J. Physiol. (Lond.) 183, 73–75P (1966).
Schulz, I., K. J. Ullrich, E. Frömter, H. Holzgreve, A. Frick u. H. Hegel: Mikropunktion und elektrische Potentialmessung an Schweißdrüsen des Menschen. Pflügers Arch. ges. Physiol. 284, 360–372 (1965).
Snedecor, G. W.: Statistical Methods. 5th ed. Ames: Iowa State University Press 1956.
Thaysen, J. H.: Handling of alkali metals by exocrine glands other than the kidney. In: The alkali metal ions in biology. Handbuch der experimentellen Pharmakologie. Ergänzungswerk Bd. 13, S. 424–507. Berlin, Göttingen, Heidelberg: Springer 1960.
— N. A. Thorn, and I. L. Schwartz: Excretion of sodium, potassium, chloride, and carbon dioxide in human parotid saliva. Amer. J. Physiol. 178, 155–159 (1954).
Young, J. A., E. Frömter, and E. Schögel: Electrolyte fluxes and potential differences in the main excretory duct of the rat submaxillary gland. Pflügers Arch. ges. Physiol. 289, 81 R (1966).
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C. J. Martin Travelling Research Fellow of the National Health and Medical Research Council of Australia; from the Medical Research Department of the Kanematsu Memorial Institute, Sydney Hospital, Sydney, N.S.W., Australia.
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Young, J.A., Schögel, E. Micropuncture investigation of sodium and potassium excretion in rat submaxillary saliva. Pflügers Archiv 291, 85–98 (1966). https://doi.org/10.1007/BF00362654
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DOI: https://doi.org/10.1007/BF00362654