Equilibrium properties of a voltage-dependent junctional conductance

Research output: Contribution to journalArticle

245 Citations (Scopus)

Abstract

The conductance of junctions between amphibian blastomeres is strongly voltage dependent. Isolated pairs of blastomeres from embryos of Ambystoma mexicanum, Xenopus laevis, and Rana pipiens were voltage clamped, and junctional current was measured during transjunctional voltage steps. The steady-state junctional conductance decreases as a steep function of transjunctional voltage of either polarity. A voltage-insensitive conductance <5% of the maximum remains at large transjunctional voltages. Equal transjunctional voltages of opposite polarities produce equal conductance changes. The conductance is half maximal at a transjunctional voltage of ~15 mV. The junctional conductance is insensitive to the potential between the inside and outside of the cells. The changes in steady-state junctional conductance may be accurately modeled for voltages of each polarity as arising from a reversible two-state system in which voltage linearly affects the energy difference between states. The voltage sensitivity can be accounted for by the movement of about six electron charges through the transjunctional voltage. The changes in junctional conductance are not consistent with a current-controlled or ionic accumulation mechanism. The authors propose that the intramembrane particles that comprise gap junctions in early amphibian embryos are voltage-sensitive channels.

Original languageEnglish (US)
Pages (from-to)77-93
Number of pages17
JournalJournal of General Physiology
Volume77
Issue number1
StatePublished - 1981

Fingerprint

Blastomeres
Amphibians
Embryonic Structures
Ambystoma mexicanum
Rana pipiens
Gap Junctions
Xenopus laevis
Electrons

ASJC Scopus subject areas

  • Physiology

Cite this

Equilibrium properties of a voltage-dependent junctional conductance. / Spray, David C.; Harris, A. L.; Bennett, Michael V. L.

In: Journal of General Physiology, Vol. 77, No. 1, 1981, p. 77-93.

Research output: Contribution to journalArticle

@article{bd8827ce1c4d4fefa5dafeb2044e7827,
title = "Equilibrium properties of a voltage-dependent junctional conductance",
abstract = "The conductance of junctions between amphibian blastomeres is strongly voltage dependent. Isolated pairs of blastomeres from embryos of Ambystoma mexicanum, Xenopus laevis, and Rana pipiens were voltage clamped, and junctional current was measured during transjunctional voltage steps. The steady-state junctional conductance decreases as a steep function of transjunctional voltage of either polarity. A voltage-insensitive conductance <5{\%} of the maximum remains at large transjunctional voltages. Equal transjunctional voltages of opposite polarities produce equal conductance changes. The conductance is half maximal at a transjunctional voltage of ~15 mV. The junctional conductance is insensitive to the potential between the inside and outside of the cells. The changes in steady-state junctional conductance may be accurately modeled for voltages of each polarity as arising from a reversible two-state system in which voltage linearly affects the energy difference between states. The voltage sensitivity can be accounted for by the movement of about six electron charges through the transjunctional voltage. The changes in junctional conductance are not consistent with a current-controlled or ionic accumulation mechanism. The authors propose that the intramembrane particles that comprise gap junctions in early amphibian embryos are voltage-sensitive channels.",
author = "Spray, {David C.} and Harris, {A. L.} and Bennett, {Michael V. L.}",
year = "1981",
language = "English (US)",
volume = "77",
pages = "77--93",
journal = "Journal of General Physiology",
issn = "0022-1295",
publisher = "Rockefeller University Press",
number = "1",

}

TY - JOUR

T1 - Equilibrium properties of a voltage-dependent junctional conductance

AU - Spray, David C.

AU - Harris, A. L.

AU - Bennett, Michael V. L.

PY - 1981

Y1 - 1981

N2 - The conductance of junctions between amphibian blastomeres is strongly voltage dependent. Isolated pairs of blastomeres from embryos of Ambystoma mexicanum, Xenopus laevis, and Rana pipiens were voltage clamped, and junctional current was measured during transjunctional voltage steps. The steady-state junctional conductance decreases as a steep function of transjunctional voltage of either polarity. A voltage-insensitive conductance <5% of the maximum remains at large transjunctional voltages. Equal transjunctional voltages of opposite polarities produce equal conductance changes. The conductance is half maximal at a transjunctional voltage of ~15 mV. The junctional conductance is insensitive to the potential between the inside and outside of the cells. The changes in steady-state junctional conductance may be accurately modeled for voltages of each polarity as arising from a reversible two-state system in which voltage linearly affects the energy difference between states. The voltage sensitivity can be accounted for by the movement of about six electron charges through the transjunctional voltage. The changes in junctional conductance are not consistent with a current-controlled or ionic accumulation mechanism. The authors propose that the intramembrane particles that comprise gap junctions in early amphibian embryos are voltage-sensitive channels.

AB - The conductance of junctions between amphibian blastomeres is strongly voltage dependent. Isolated pairs of blastomeres from embryos of Ambystoma mexicanum, Xenopus laevis, and Rana pipiens were voltage clamped, and junctional current was measured during transjunctional voltage steps. The steady-state junctional conductance decreases as a steep function of transjunctional voltage of either polarity. A voltage-insensitive conductance <5% of the maximum remains at large transjunctional voltages. Equal transjunctional voltages of opposite polarities produce equal conductance changes. The conductance is half maximal at a transjunctional voltage of ~15 mV. The junctional conductance is insensitive to the potential between the inside and outside of the cells. The changes in steady-state junctional conductance may be accurately modeled for voltages of each polarity as arising from a reversible two-state system in which voltage linearly affects the energy difference between states. The voltage sensitivity can be accounted for by the movement of about six electron charges through the transjunctional voltage. The changes in junctional conductance are not consistent with a current-controlled or ionic accumulation mechanism. The authors propose that the intramembrane particles that comprise gap junctions in early amphibian embryos are voltage-sensitive channels.

UR - http://www.scopus.com/inward/record.url?scp=0019365945&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0019365945&partnerID=8YFLogxK

M3 - Article

C2 - 6259274

AN - SCOPUS:0019365945

VL - 77

SP - 77

EP - 93

JO - Journal of General Physiology

JF - Journal of General Physiology

SN - 0022-1295

IS - 1

ER -