Title: Chapter 5 Intracellular Potassium Activity Measurements in Single Proximal Tubules of Necturus Kidney
Abstract: This chapter provides an overview of the experiments that were carried out to investigate the relationship between proximal tubular cell potassium activities and the rate of transepithelial sodium transport during several maneuvers. The analyses were performed to compare cellular potassium activities in a variety of widely varying experimental conditions with chemically measured potassium concentrations in the view of reports that large differences exist between those two types of potassium measurements. The data presented in the chapter indicates that variations in extracellular pH and bicarbonate levels had significant effects upon the peritubular membrane potential and cellular potassium activities. The values for intracellular potassium indicate that potassium ions were not in electrochemical equilibrium across the peritubular membrane of proximal tubule cells of Necturus. While cell potassium levels were sharply reduced by ouabain, they were well maintained in experimental conditions known to decrease the net sodium transport across the amphibian proximal tubular epithelium. It is possible that both maneuvers affect sodium transport by the common mechanism of lowering cell potassium; however, whether low cellular potassium affects sodium entry down an electrochemical potential gradient across the luminal cell membrane directly, or modulates the efficiency of peritubular active sodium extrusion, is presently unknown and needs further investigation.
Publication Year: 1980
Publication Date: 1980-01-01
Language: en
Type: book-chapter
Indexed In: ['crossref']
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Cited By Count: 1
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