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WATER AND ELECTROLYTE EXCRETION IN THE CAT SUBMAXILLARY GLAND STUDIED USING MICROPUNCTURE AND DUCT CANNULATION TECHNIQUES
Author(s) -
Kaladelfos G,
Young JA
Publication year - 1974
Publication title -
australian journal of experimental biology and medical science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0004-945X
DOI - 10.1038/icb.1974.5
Subject(s) - medicine , stimulation , endocrinology , bicarbonate , potassium , secretion , chemistry , saliva , submandibular gland , sodium , duct (anatomy) , excretion , submaxillary gland , electrolyte , tubular fluid , biology , anatomy , reabsorption , organic chemistry , electrode
Summary Studies on the electrolyte composition of the acinar (or primary) secretion and the final saliva of the cat submaxillary gland undergoing parasympatho‐ and sympathomimetic stimulation have been undertaken using micropuncture and duct cannulation techniques for sample collection. The work was undertaken to see to what extent the two‐stage secretory model developed previously for rat salivary glands would hold for rather different glands of other species. We find that in general terms the same two‐stage model is applicable. The primary secretion in both species has plasma‐like sodium and chloride concentrations and potassium concentrations about twice those of plasma; gland stimulation does not greatly alter the composition of this fluid. In the secondary stage, during passage of this fluid along the gland excurrent ducts, there is in both species, extensive ductal absorption of sodium and chloride, although for the cat the absorptive mechanism is more easily saturable. Unlike rat submaxillary ducts, however, those of the cat appear to secrete little potassium, and gland stimulation does not increase the secretory rate of this ion, so that the phenomenon termed acino‐tubular balance is not observed. Although both ducts may secrete bicarbonate this is much more conspicuous for the rat. In contrast to parasympathomimetic stimulation, the effects of sympathomimetic stimulation on the two glands were totally different. In the cat a much more vigorous secretory response was obtained than in the rat but the striking elevation of salivary potassium and bicarbonate concentrations to values in excess of 100 mM seen in the rat did not occur. It is concluded that while a two‐stage hypothesis may account for secretion of water and electrolytes in many salivary glands, the role of ductal stimulation in the secondary stage and the relative roles of sympathetic and parasympathetic stimulation may vary greatly among species.