Journal article
Intracellular chloride activities in the isolated perfused shark rectal gland
The American journal of physiology, Vol.245(5 Pt 1), pp.F640-644
11/1983
DOI: 10.1152/ajprenal.1983.245.5.F640
PMID: 6638184
Abstract
The isolated, perfused shark rectal gland secretes Cl when stimulated with adenosine 3',5'-cyclic monophosphate (cAMP). To investigate the mechanism of secretion, we used Cl-selective and conventional (KCl-filled) microelectrodes to measure the intracellular Cl activity (aClc). Under nonsecreting conditions, the electrical potential difference across the basolateral membrane (psi b) was -78 m V and aClc was 57 mM, a value seven times greater than predicted for electrochemical equilibrium across the basolateral membrane. When theophylline and 8-bromo-cAMP were added to the perfusate, the transglandular electrical potential difference doubled and the rate of fluid secretion increased 20-fold; however, neither psi b nor aClc changed. During both nonsecreting and secreting conditions the intracellular accumulation of Cl results in an electrochemical potential difference favoring Cl exit across the apical cell membrane. The constancy of aClc despite the variation in secretion rate suggests that stimulation is associated with an equivalent enhancement of net Cl movement across both the apical and basolateral membranes. When stimulated glands were perfused with Na-free (choline) Ringer, secretion was abolished and aClc fell toward the value predicted for electrochemical equilibrium. These findings suggest that the "uphill" step in Cl secretion lies at the basolateral membrane, where cellular Cl accumulation probably involves secondary active transport; i.e., Cl entry is driven by an inwardly directed electrochemical potential difference for Na.
Details
- Title: Subtitle
- Intracellular chloride activities in the isolated perfused shark rectal gland
- Creators
- Michael J WelshPhilip L SmithRaymond A Frizzell
- Resource Type
- Journal article
- Publication Details
- The American journal of physiology, Vol.245(5 Pt 1), pp.F640-644
- DOI
- 10.1152/ajprenal.1983.245.5.F640
- PMID
- 6638184
- NLM abbreviation
- Am J Physiol
- ISSN
- 0002-9513
- eISSN
- 2163-5773
- Publisher
- American Physiological Society; United States
- Grant note
- AM-05973 / NIADDK NIH HHS AM-27524 / NIADDK NIH HHS HL-07159 / NHLBI NIH HHS
- Language
- English
- Date published
- 11/1983
- Academic Unit
- Neurology; Molecular Physiology and Biophysics; Pulmonary, Critical Care, and Occupational Medicine; Fraternal Order of Eagles Diabetes Research Center; Neurosurgery; Internal Medicine
- Record Identifier
- 9984020865902771
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