What question did this study set out to answer?

To investigate the mechanisms and pharmacology of potassium exit across the basolateral membrane of rabbit cortical thick ascending limb cells.

January 1, 1998Cellular Physiology and Biochemistry

A Ba2+-Insensitive K+ Conductance in the Basolateral Membrane of Rabbit Cortical Thick Ascending Limb Cells

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Population

Microperfused rabbit cortical thick ascending limbs (cTALs)

Comparison

Bath K+ concentration increases and application… vs Baseline conditions (4 mmol/l K+)

Design

Preclinical

Authors

ASAntonio Di StefanoUniversity of Chieti-Pescara RGR. GregerGoethe University Frankfurt EDE. DesfleursNovartis (France)

Discussion

Member takes

Implication

No immediate clinical implications for renal care; leaves open the conductance's role in human TAL physiology.

Key Points

To investigate the mechanisms and pharmacology of potassium exit across the basolateral membrane of rabbit cortical thick ascending limb cells.
Microperfused isolated rabbit cortical thick ascending limbs while recording transepithelial potential difference, basolateral membrane potential difference, and basolateral fractional resistance.
Administered increasing concentrations of peritubular potassium (4 to 10, 25, and 50 mmol/l) in the presence and absence of ion transport modulators, including barium, furosemide, and various potassium channel inhibitors.
Stepwise elevation of bath potassium produced a concentration-dependent basolateral membrane depolarization and decreased basolateral fractional resistance, which was insensitive to the chloride channel blocker NPPB.
Extracellular barium failed to suppress potassium-induced reductions in basolateral fractional resistance, and depolarizations were insensitive to tetraethylammonium, charybdotoxin, apamin, and verapamil.
Barium-induced depolarizations were completely prevented by furosemide, indicating that barium acts by inhibiting basolateral potassium-chloride cotransport rather than the basolateral potassium conductance.

Structured PICO

Population

Microperfused rabbit cortical thick ascending limbs (cTALs)

Intervention

Bath K+ concentration increases (from 4 to 10, 25, 50 mmol/l) and application of Ba2+, NPPB, furosemide, tetraethylammonium, charybdotoxin, apamin, and verapamil

Comparator

Baseline conditions (4 mmol/l K+)

Outcome

Transepithelial and transmembrane potential difference (PDte, PDbl) and fractional resistance of the basolateral membrane (FRbl)surrogate

The study identifies a Ba2+-insensitive K+ conductance in the basolateral membrane of rabbit cortical thick ascending limb cells.

Cite This Study

Stefano et al. (1998) studied this question.

synapsesocial.com/papers/6a8ba2e1d5d4290f64f47ac1 https://doi.org/10.1159/000016273

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A Ba2+-Insensitive K+ Conductance in the Basolateral Membrane of Rabbit Cortical Thick Ascending Limb Cells

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

A Ba2+-Insensitive K+ Conductance in the Basolateral Membrane of Rabbit Cortical Thick Ascending Limb Cells

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider