What question did this study set out to answer?

To determine the electrophysiological mechanisms and single-channel properties underlying cAMP-stimulated chloride efflux in Caco-2 intestinal epithelial cells.

January 1, 1992AJP Cell Physiology

cAMP-activated chloride conductance in the colonic cell line, Caco-2

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Population

Caco-2 monolayers (colonic cell line)

Comparison

cAMP stimulation vs Unstimulated state / baseline

Design

Preclinical

Authors

CBChristine E. BearUniversity of Toronto EREvangelica ReyesHospital for Sick Children

Discussion

Member takes

Implication

cAMP activates anion channels in Caco-2 epithelia; leaves open translation to secretory disorders pending in vivo studies.

Key Points

To determine the electrophysiological mechanisms and single-channel properties underlying cAMP-stimulated chloride efflux in Caco-2 intestinal epithelial cells.
Assayed 125I efflux rates in Caco-2 monolayers stimulated with a cocktail of 100 µM DBcAMP, 10 µM forskolin, and 1 mM IBMX, in the presence and absence of valinomycin and high extracellular KCl.
Applied whole-cell and cell-attached patch-clamp electrophysiology to evaluate current-voltage relationships, gating kinetics, and anion selectivity.
cAMP cocktail stimulation significantly increased 125I efflux rate (P < 0.05), which was markedly reduced upon membrane potential dissipation with 4.5 µM valinomycin and 135 mM KCl.
Whole-cell currents displayed linear current-voltage relationships without time-dependent gating and showed an anion selectivity sequence of PCl > PI > Pgluconate.
Cell-attached recordings identified single chloride channels activating within 20–30 s of cAMP exposure, exhibiting slope conductances of 3.2 ± 0.6 pS at hyperpolarizing potentials and 7.4 ± 0.3 pS at depolarizing potentials.

Structured PICO

Population

Caco-2 monolayers (colonic cell line)

Intervention

cAMP stimulation (cocktail containing 100 microM dibutyryl cAMP, 10 microM forskolin, and 1 mM 3-isobutyl-1-methylxanthine)

Comparator

Unstimulated state / baseline

Outcome

Cl- efflux rates (measured by 125I efflux) and electrophysiological properties (whole cell currents, single Cl- channels)surrogate

This basic science study demonstrates that cAMP stimulates anion efflux through a conductive pore or channel in Caco-2 colonic cells.

Cite This Study

Bear et al. (1992) studied this question.

synapsesocial.com/papers/6a714023e5469ee92be1d4a7 https://doi.org/10.1152/ajpcell.1992.262.1.c251

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cAMP-activated chloride conductance in the colonic cell line, Caco-2

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

cAMP-activated chloride conductance in the colonic cell line, Caco-2

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider