Gap junctional conductance is a simple and sensitive function of intracellular pH

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Abstract

The pH of the cytoplasm (pHt) measured with pH-sensitive microelectrodes in cleavage-stage blastomeres of amphibian (Ambystoma) and teleost (Fundulus) embryos is about 7.7. In electrotonically coupled cell pairs, junctional conductance is rapidly and reversibly reduced by acidification of the cytoplasm. The relation between junctional conductance and pHt is the same for increasing and decreasing pH and is independent of the rate of change over a wide range. The relation is well fitted by a Hill curve with K=50 nM (pK=7.3) and n=4 to 5. The closure of gap junction channels at low pH t appears to be a cooperative process involving several charged sites. The absence of hysteresis and identity of effects for fast and slow pHt changes implies that protons act directly on the channel macromolecules and not through an intermediate in the cytoplasm.

Original languageEnglish (US)
Pages (from-to)712-715
Number of pages4
JournalSciences
Volume211
Issue number4483
StatePublished - 1981

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Cytoplasm
Fundulidae
Ambystoma
Blastomeres
Gap Junctions
Microelectrodes
Amphibians
Protons
Embryonic Structures

ASJC Scopus subject areas

  • General

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Gap junctional conductance is a simple and sensitive function of intracellular pH. / Spray, David C.; Harris, A. L.; Bennett, Michael V. L.

In: Sciences, Vol. 211, No. 4483, 1981, p. 712-715.

Research output: Contribution to journalArticle

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AU - Harris, A. L.

AU - Bennett, Michael V. L.

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N2 - The pH of the cytoplasm (pHt) measured with pH-sensitive microelectrodes in cleavage-stage blastomeres of amphibian (Ambystoma) and teleost (Fundulus) embryos is about 7.7. In electrotonically coupled cell pairs, junctional conductance is rapidly and reversibly reduced by acidification of the cytoplasm. The relation between junctional conductance and pHt is the same for increasing and decreasing pH and is independent of the rate of change over a wide range. The relation is well fitted by a Hill curve with K=50 nM (pK=7.3) and n=4 to 5. The closure of gap junction channels at low pH t appears to be a cooperative process involving several charged sites. The absence of hysteresis and identity of effects for fast and slow pHt changes implies that protons act directly on the channel macromolecules and not through an intermediate in the cytoplasm.

AB - The pH of the cytoplasm (pHt) measured with pH-sensitive microelectrodes in cleavage-stage blastomeres of amphibian (Ambystoma) and teleost (Fundulus) embryos is about 7.7. In electrotonically coupled cell pairs, junctional conductance is rapidly and reversibly reduced by acidification of the cytoplasm. The relation between junctional conductance and pHt is the same for increasing and decreasing pH and is independent of the rate of change over a wide range. The relation is well fitted by a Hill curve with K=50 nM (pK=7.3) and n=4 to 5. The closure of gap junction channels at low pH t appears to be a cooperative process involving several charged sites. The absence of hysteresis and identity of effects for fast and slow pHt changes implies that protons act directly on the channel macromolecules and not through an intermediate in the cytoplasm.

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