Single-channel events and gating behavior of the cardiac gap junction channel

J. M. Burt, David C. Spray

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Abstract

The activity of gap junction channels between pairs of neonatal rat heart cells in culture was studied under control conditions and during uncoupling procedures by using dual whole-cell voltage clamp techniques. Under control conditions gap junctional conductance ranged from 0.05 to 34 nS. In cell pairs exhibiting low gap junctional conductance (<500 pS), single-channel events with a unitary conductance of 53 ± 2 pS (5 experiments; 186 events) were apparent. Event duration and open-time probability were estimated to be 0.95 sec and 0.17, respectively. When the junctional conductance in well-coupled cell pairs (with initial junctional conductance, >5 nS) was reduced by cytoplasmic acidification or application of heptanol, single-channel events could be visualized. Compared to low-conductance controls, unitary channel conductance was unaltered (for acidification the conductance was 58 ± 3 pS in 11 experiments with 253 events; for heptanol the conductance was 61 ± 1 pS in experiments with 171 events), while the probability of channels being open was decreased. The constancy of unitary channel conductance under control conditions and during uncoupling procedures suggests that opening and closing of the gap junction channel are all-or-none processes during which no stable subconductance states are formed.

Original languageEnglish (US)
Pages (from-to)3431-3434
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Volume85
Issue number10
StatePublished - 1988
Externally publishedYes

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Heptanol
Gap Junctions
Patch-Clamp Techniques
Cell Culture Techniques

ASJC Scopus subject areas

  • General
  • Genetics

Cite this

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abstract = "The activity of gap junction channels between pairs of neonatal rat heart cells in culture was studied under control conditions and during uncoupling procedures by using dual whole-cell voltage clamp techniques. Under control conditions gap junctional conductance ranged from 0.05 to 34 nS. In cell pairs exhibiting low gap junctional conductance (<500 pS), single-channel events with a unitary conductance of 53 ± 2 pS (5 experiments; 186 events) were apparent. Event duration and open-time probability were estimated to be 0.95 sec and 0.17, respectively. When the junctional conductance in well-coupled cell pairs (with initial junctional conductance, >5 nS) was reduced by cytoplasmic acidification or application of heptanol, single-channel events could be visualized. Compared to low-conductance controls, unitary channel conductance was unaltered (for acidification the conductance was 58 ± 3 pS in 11 experiments with 253 events; for heptanol the conductance was 61 ± 1 pS in experiments with 171 events), while the probability of channels being open was decreased. The constancy of unitary channel conductance under control conditions and during uncoupling procedures suggests that opening and closing of the gap junction channel are all-or-none processes during which no stable subconductance states are formed.",
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T1 - Single-channel events and gating behavior of the cardiac gap junction channel

AU - Burt, J. M.

AU - Spray, David C.

PY - 1988

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N2 - The activity of gap junction channels between pairs of neonatal rat heart cells in culture was studied under control conditions and during uncoupling procedures by using dual whole-cell voltage clamp techniques. Under control conditions gap junctional conductance ranged from 0.05 to 34 nS. In cell pairs exhibiting low gap junctional conductance (<500 pS), single-channel events with a unitary conductance of 53 ± 2 pS (5 experiments; 186 events) were apparent. Event duration and open-time probability were estimated to be 0.95 sec and 0.17, respectively. When the junctional conductance in well-coupled cell pairs (with initial junctional conductance, >5 nS) was reduced by cytoplasmic acidification or application of heptanol, single-channel events could be visualized. Compared to low-conductance controls, unitary channel conductance was unaltered (for acidification the conductance was 58 ± 3 pS in 11 experiments with 253 events; for heptanol the conductance was 61 ± 1 pS in experiments with 171 events), while the probability of channels being open was decreased. The constancy of unitary channel conductance under control conditions and during uncoupling procedures suggests that opening and closing of the gap junction channel are all-or-none processes during which no stable subconductance states are formed.

AB - The activity of gap junction channels between pairs of neonatal rat heart cells in culture was studied under control conditions and during uncoupling procedures by using dual whole-cell voltage clamp techniques. Under control conditions gap junctional conductance ranged from 0.05 to 34 nS. In cell pairs exhibiting low gap junctional conductance (<500 pS), single-channel events with a unitary conductance of 53 ± 2 pS (5 experiments; 186 events) were apparent. Event duration and open-time probability were estimated to be 0.95 sec and 0.17, respectively. When the junctional conductance in well-coupled cell pairs (with initial junctional conductance, >5 nS) was reduced by cytoplasmic acidification or application of heptanol, single-channel events could be visualized. Compared to low-conductance controls, unitary channel conductance was unaltered (for acidification the conductance was 58 ± 3 pS in 11 experiments with 253 events; for heptanol the conductance was 61 ± 1 pS in experiments with 171 events), while the probability of channels being open was decreased. The constancy of unitary channel conductance under control conditions and during uncoupling procedures suggests that opening and closing of the gap junction channel are all-or-none processes during which no stable subconductance states are formed.

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