Potassium uptake in the mouse submandibular gland is dependent on chloride and sodium and abolished by piretanide.

Academic Article

Abstract

  • Nervous or hormonal stimulation of salivary secretion in vivo is associated with a pronounced efflux of K+ from the secretory, acinar cells into the blood. This K+ efflux is followed in the post‐stimulus period by a reuptake of K+ into the glandular tissue. In the present study we monitor the changes in [K+] of physiological solutions perfusing a flow chamber containing isolated segments of mouse submandibular glands. Nervous stimulation or the application of exogenous acetylcholine (ACh, 10(‐5) M) to the isolated glandular tissue results in characteristic changes in the [K+] of the superfusate, indicating net K+ release followed by K+ reuptake. The post‐stimulus reuptake of K+ is shown to be susceptible to blockade by either ouabain (10(‐3) M) or piretanide (10(‐4) M). The reuptake was markedly attenuated if Cl‐ in the superfusate was replaced by either NO3‐ or SO4(2‐). The K+ uptake was, however, unaffected when Br‐ replaced Cl‐ in the superfusate. Similar effects were observed in the unstimulated glandular tissues. The introduction of Cl‐(‐)free media containing either NO3‐ or SO4(2‐) resulted in a loss of K+ from the tissue which was followed, upon reintroduction of Cl‐, by a pronounced uptake of K+. When Br‐ was substituted for Cl‐ there was very little change in [K+] upon removal or reintroduction of Cl‐. The uptake of K+ induced by reintroduction of Cl‐ after a period of NO3‐ or SO4(2‐) superfusion was blocked by both ouabain and piretanide. This uptake of K+ was also dependent on the presence of extracellular Na+. Both Cl‐ and Na+ had to be present in the superfusing medium for K+ uptake to be fully manifest. These findings indicate that the K+ uptake observed in both the resting and stimulated submandibular gland cannot be explained as solely due to the activity of the Na+‐K+‐adenosine triphosphatase (Na+‐K+‐ATPase). The demonstrated anionic selectivity, dependence on extracellular Na+ and susceptibility to blockade by the diuretic piretanide would strongly suggest that a coupled Na+‐K+‐Cl‐ co‐transport system operates in submandibular glands as it does in other transporting epithelia to achieve K+ uptake. © 1986 The Physiological Society
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    Digital Object Identifier (doi)

    Author List

  • Exley PM; Fuller CM; Gallacher DV
  • Start Page

  • 97
  • End Page

  • 108
  • Volume

  • 378
  • Issue

  • 1