Complex channel activity recorded from rat liver gap junctional membranes incorporated into lipid bilayers.

A. C. Campos-De-Carvalho, E. L. Hertzberg, David C. Spray

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

1. Channels from isolated liver junctional membranes were incorporated into lipid bilayers and studied under voltage clamp conditions. Detergent treatment of junctional membrane fragments greatly increased the incidence of channel incorporation but did not noticeably alter the properties of the incorporated channels. Incorporation resulted in channel activity displaying an approximately symmetric voltage dependence in which conductance was decreased with imposed transmembrane voltages exceeding +/- 20 mV. A residual voltage-independent conductance was also detected in membranes in which liver junctional membranes were incorporated. The magnitude of this voltage-insensitive component varied from less than 20% to more than 75% of the total conductance. 2. These results are generally similar to those described by Young, Cohn and Gilula (Cell, 48: 733-743, 1987) in incorporation experiments following detergent treatment of isolated gap junction membranes. However, we interpret these data as indicating the existence of distinct channel populations in the incorporated membrane fractions. Our results suggest that a population of larger conductance channels (greater than or equal to 150 pS) contributes the voltage-dependent component of the membrane conductance, while smaller channels (unitary conductance about 50-150 pS) contribute the voltage-independent component. The biophysical properties of the larger channel are comparable to those seen in communication-deficient cells transfected with connexin32, confirming a report describing conductance of bilayers in which electroeluted 27-kDa liver gap junction protein was inserted. 3. These findings indicate that connexin32 comprises the larger, voltage-dependent channels seen in the bilayer experiments in which liver junctional membranes are incorporated.

Original languageEnglish (US)
Pages (from-to)527-537
Number of pages11
JournalBrazilian Journal of Medical and Biological Research
Volume24
Issue number5
StatePublished - 1991
Externally publishedYes

Fingerprint

lipid bilayers
Lipid bilayers
Lipid Bilayers
Liver
Rats
Membranes
liver
rats
Electric potential
detergents
connexins
gap junctions
Detergents
animal communication
cells
incidence
Connexins
Gap Junctions
Clamping devices
Cell Communication

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Medicine (miscellaneous)

Cite this

Complex channel activity recorded from rat liver gap junctional membranes incorporated into lipid bilayers. / Campos-De-Carvalho, A. C.; Hertzberg, E. L.; Spray, David C.

In: Brazilian Journal of Medical and Biological Research, Vol. 24, No. 5, 1991, p. 527-537.

Research output: Contribution to journalArticle

@article{2d6d891c84054987ab30f26b9d36ef6d,
title = "Complex channel activity recorded from rat liver gap junctional membranes incorporated into lipid bilayers.",
abstract = "1. Channels from isolated liver junctional membranes were incorporated into lipid bilayers and studied under voltage clamp conditions. Detergent treatment of junctional membrane fragments greatly increased the incidence of channel incorporation but did not noticeably alter the properties of the incorporated channels. Incorporation resulted in channel activity displaying an approximately symmetric voltage dependence in which conductance was decreased with imposed transmembrane voltages exceeding +/- 20 mV. A residual voltage-independent conductance was also detected in membranes in which liver junctional membranes were incorporated. The magnitude of this voltage-insensitive component varied from less than 20{\%} to more than 75{\%} of the total conductance. 2. These results are generally similar to those described by Young, Cohn and Gilula (Cell, 48: 733-743, 1987) in incorporation experiments following detergent treatment of isolated gap junction membranes. However, we interpret these data as indicating the existence of distinct channel populations in the incorporated membrane fractions. Our results suggest that a population of larger conductance channels (greater than or equal to 150 pS) contributes the voltage-dependent component of the membrane conductance, while smaller channels (unitary conductance about 50-150 pS) contribute the voltage-independent component. The biophysical properties of the larger channel are comparable to those seen in communication-deficient cells transfected with connexin32, confirming a report describing conductance of bilayers in which electroeluted 27-kDa liver gap junction protein was inserted. 3. These findings indicate that connexin32 comprises the larger, voltage-dependent channels seen in the bilayer experiments in which liver junctional membranes are incorporated.",
author = "Campos-De-Carvalho, {A. C.} and Hertzberg, {E. L.} and Spray, {David C.}",
year = "1991",
language = "English (US)",
volume = "24",
pages = "527--537",
journal = "Brazilian Journal of Medical and Biological Research",
issn = "0100-879X",
publisher = "Associacao Brasileira de Divulgacao Cientifica",
number = "5",

}

TY - JOUR

T1 - Complex channel activity recorded from rat liver gap junctional membranes incorporated into lipid bilayers.

AU - Campos-De-Carvalho, A. C.

AU - Hertzberg, E. L.

AU - Spray, David C.

PY - 1991

Y1 - 1991

N2 - 1. Channels from isolated liver junctional membranes were incorporated into lipid bilayers and studied under voltage clamp conditions. Detergent treatment of junctional membrane fragments greatly increased the incidence of channel incorporation but did not noticeably alter the properties of the incorporated channels. Incorporation resulted in channel activity displaying an approximately symmetric voltage dependence in which conductance was decreased with imposed transmembrane voltages exceeding +/- 20 mV. A residual voltage-independent conductance was also detected in membranes in which liver junctional membranes were incorporated. The magnitude of this voltage-insensitive component varied from less than 20% to more than 75% of the total conductance. 2. These results are generally similar to those described by Young, Cohn and Gilula (Cell, 48: 733-743, 1987) in incorporation experiments following detergent treatment of isolated gap junction membranes. However, we interpret these data as indicating the existence of distinct channel populations in the incorporated membrane fractions. Our results suggest that a population of larger conductance channels (greater than or equal to 150 pS) contributes the voltage-dependent component of the membrane conductance, while smaller channels (unitary conductance about 50-150 pS) contribute the voltage-independent component. The biophysical properties of the larger channel are comparable to those seen in communication-deficient cells transfected with connexin32, confirming a report describing conductance of bilayers in which electroeluted 27-kDa liver gap junction protein was inserted. 3. These findings indicate that connexin32 comprises the larger, voltage-dependent channels seen in the bilayer experiments in which liver junctional membranes are incorporated.

AB - 1. Channels from isolated liver junctional membranes were incorporated into lipid bilayers and studied under voltage clamp conditions. Detergent treatment of junctional membrane fragments greatly increased the incidence of channel incorporation but did not noticeably alter the properties of the incorporated channels. Incorporation resulted in channel activity displaying an approximately symmetric voltage dependence in which conductance was decreased with imposed transmembrane voltages exceeding +/- 20 mV. A residual voltage-independent conductance was also detected in membranes in which liver junctional membranes were incorporated. The magnitude of this voltage-insensitive component varied from less than 20% to more than 75% of the total conductance. 2. These results are generally similar to those described by Young, Cohn and Gilula (Cell, 48: 733-743, 1987) in incorporation experiments following detergent treatment of isolated gap junction membranes. However, we interpret these data as indicating the existence of distinct channel populations in the incorporated membrane fractions. Our results suggest that a population of larger conductance channels (greater than or equal to 150 pS) contributes the voltage-dependent component of the membrane conductance, while smaller channels (unitary conductance about 50-150 pS) contribute the voltage-independent component. The biophysical properties of the larger channel are comparable to those seen in communication-deficient cells transfected with connexin32, confirming a report describing conductance of bilayers in which electroeluted 27-kDa liver gap junction protein was inserted. 3. These findings indicate that connexin32 comprises the larger, voltage-dependent channels seen in the bilayer experiments in which liver junctional membranes are incorporated.

UR - http://www.scopus.com/inward/record.url?scp=0026275576&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0026275576&partnerID=8YFLogxK

M3 - Article

VL - 24

SP - 527

EP - 537

JO - Brazilian Journal of Medical and Biological Research

JF - Brazilian Journal of Medical and Biological Research

SN - 0100-879X

IS - 5

ER -