ISSN:
1432-1424
Keywords:
proximal tubule
;
cable analysis
;
membrane resistances
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary Individual resistances of the apical cell membrane,R a , the basolateral cell membrane,R bl , and the paracellular shunt,R s , were determined in theNecturus proximal tubule using a set of three electrical parameters. Four electrical parameters were measured: the transepithelial resistance, (R te ), the apical and basolateral cell membrane resistance in parallel, (R Z free-flow tubules), the basolateral cell membrane resistance in oil-filled tubules, (R Z oil-filled), and the ratio of apical and basolateral cell membrane resistance (R a /R bl ).R te was determined from an analysis of the spatial decay of luminal voltage following luminal current injection.R Z free-flow andR Z oil-filled were measured by the analysis of the spatial decay of intracellular voltage deflections following cellular current injection in free flow and oil-filled tubules, respectively.R a /R bl was estimated from the ratio of voltage deflections across the apical and basolateral cell membranes following transepithelial current injection. In addition, the magnitude of cellular and luminal cable interactions was evaluated, by comparing the spatial decay of voltage deflections in the cell and in the lumen following intracellular current injection. The combined cell membrane resistance (R a +R bl ) is between one to two orders of magnitude greater than the paracellular resistance. This result supports the view that theNecturus proximal tubule is a leaky epithelium.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01868657
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