Desensitization mechanism of GABA receptors revealed by single oocyte binding and receptor function

YongChang Chang, Emmanuel Ghansah, Yonghui Chen, Jiawei Ye, David S Weiss

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

Prolonged exposure of most fast neurotransmitter-operated ion channels to agonist drives the receptors into a nonfunctional, or desensitized, state. Despite extensive investigation, desensitization remains a thoroughly characterized, yet poorly understood, process. Part of the difficulty in elucidating the mechanism of desensitization has been an inability to resolve the kinetics of both agonist binding and functional desensitization in the same set of operable receptors. To overcome this limitation, we applied single oocyte 3H-ligand binding and two-electrode voltage clamp to oocytes expressing recombinant α1β2γ2 GABA receptors. Using this approach, we report several observations fundamental to the mechanism of desensitization. First, we confirm that desensitization reversibly shifts GABA receptors into a high-affinity state. For [3H]GABA binding, the half-maximal binding of the desensitized state was ∼0.040 μM. Second, we show that, upon agonist removal, this high-affinity state disappears with a time constant of 127 ± 12 sec (n = 4), similar to the time constant for functional recovery from desensitization of 124 ± 26 sec (n = 5). [3H]GABA, however, dissociates fourfold faster (τ = 30 ± 2 sec; n = 3) than functional recovery, indicating that desensitized receptors need not be bound by GABA. These data provide direct evidence for a cyclical model of receptor desensitization.

Original languageEnglish (US)
Pages (from-to)7982-7990
Number of pages9
JournalJournal of Neuroscience
Volume22
Issue number18
StatePublished - Sep 15 2002
Externally publishedYes

Fingerprint

GABA Receptors
gamma-Aminobutyric Acid
Oocytes
Ion Channels
Neurotransmitter Agents
Electrodes
Ligands

Keywords

  • Affinity
  • Binding
  • Desensitization
  • GABA receptor
  • Kinetics
  • Oocyte

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Desensitization mechanism of GABA receptors revealed by single oocyte binding and receptor function. / Chang, YongChang; Ghansah, Emmanuel; Chen, Yonghui; Ye, Jiawei; Weiss, David S.

In: Journal of Neuroscience, Vol. 22, No. 18, 15.09.2002, p. 7982-7990.

Research output: Contribution to journalArticle

Chang, YongChang ; Ghansah, Emmanuel ; Chen, Yonghui ; Ye, Jiawei ; Weiss, David S. / Desensitization mechanism of GABA receptors revealed by single oocyte binding and receptor function. In: Journal of Neuroscience. 2002 ; Vol. 22, No. 18. pp. 7982-7990.
@article{625e672ad67143a6af4ff8d1d03b8293,
title = "Desensitization mechanism of GABA receptors revealed by single oocyte binding and receptor function",
abstract = "Prolonged exposure of most fast neurotransmitter-operated ion channels to agonist drives the receptors into a nonfunctional, or desensitized, state. Despite extensive investigation, desensitization remains a thoroughly characterized, yet poorly understood, process. Part of the difficulty in elucidating the mechanism of desensitization has been an inability to resolve the kinetics of both agonist binding and functional desensitization in the same set of operable receptors. To overcome this limitation, we applied single oocyte 3H-ligand binding and two-electrode voltage clamp to oocytes expressing recombinant α1β2γ2 GABA receptors. Using this approach, we report several observations fundamental to the mechanism of desensitization. First, we confirm that desensitization reversibly shifts GABA receptors into a high-affinity state. For [3H]GABA binding, the half-maximal binding of the desensitized state was ∼0.040 μM. Second, we show that, upon agonist removal, this high-affinity state disappears with a time constant of 127 ± 12 sec (n = 4), similar to the time constant for functional recovery from desensitization of 124 ± 26 sec (n = 5). [3H]GABA, however, dissociates fourfold faster (τ = 30 ± 2 sec; n = 3) than functional recovery, indicating that desensitized receptors need not be bound by GABA. These data provide direct evidence for a cyclical model of receptor desensitization.",
keywords = "Affinity, Binding, Desensitization, GABA receptor, Kinetics, Oocyte",
author = "YongChang Chang and Emmanuel Ghansah and Yonghui Chen and Jiawei Ye and Weiss, {David S}",
year = "2002",
month = "9",
day = "15",
language = "English (US)",
volume = "22",
pages = "7982--7990",
journal = "Journal of Neuroscience",
issn = "0270-6474",
publisher = "Society for Neuroscience",
number = "18",

}

TY - JOUR

T1 - Desensitization mechanism of GABA receptors revealed by single oocyte binding and receptor function

AU - Chang, YongChang

AU - Ghansah, Emmanuel

AU - Chen, Yonghui

AU - Ye, Jiawei

AU - Weiss, David S

PY - 2002/9/15

Y1 - 2002/9/15

N2 - Prolonged exposure of most fast neurotransmitter-operated ion channels to agonist drives the receptors into a nonfunctional, or desensitized, state. Despite extensive investigation, desensitization remains a thoroughly characterized, yet poorly understood, process. Part of the difficulty in elucidating the mechanism of desensitization has been an inability to resolve the kinetics of both agonist binding and functional desensitization in the same set of operable receptors. To overcome this limitation, we applied single oocyte 3H-ligand binding and two-electrode voltage clamp to oocytes expressing recombinant α1β2γ2 GABA receptors. Using this approach, we report several observations fundamental to the mechanism of desensitization. First, we confirm that desensitization reversibly shifts GABA receptors into a high-affinity state. For [3H]GABA binding, the half-maximal binding of the desensitized state was ∼0.040 μM. Second, we show that, upon agonist removal, this high-affinity state disappears with a time constant of 127 ± 12 sec (n = 4), similar to the time constant for functional recovery from desensitization of 124 ± 26 sec (n = 5). [3H]GABA, however, dissociates fourfold faster (τ = 30 ± 2 sec; n = 3) than functional recovery, indicating that desensitized receptors need not be bound by GABA. These data provide direct evidence for a cyclical model of receptor desensitization.

AB - Prolonged exposure of most fast neurotransmitter-operated ion channels to agonist drives the receptors into a nonfunctional, or desensitized, state. Despite extensive investigation, desensitization remains a thoroughly characterized, yet poorly understood, process. Part of the difficulty in elucidating the mechanism of desensitization has been an inability to resolve the kinetics of both agonist binding and functional desensitization in the same set of operable receptors. To overcome this limitation, we applied single oocyte 3H-ligand binding and two-electrode voltage clamp to oocytes expressing recombinant α1β2γ2 GABA receptors. Using this approach, we report several observations fundamental to the mechanism of desensitization. First, we confirm that desensitization reversibly shifts GABA receptors into a high-affinity state. For [3H]GABA binding, the half-maximal binding of the desensitized state was ∼0.040 μM. Second, we show that, upon agonist removal, this high-affinity state disappears with a time constant of 127 ± 12 sec (n = 4), similar to the time constant for functional recovery from desensitization of 124 ± 26 sec (n = 5). [3H]GABA, however, dissociates fourfold faster (τ = 30 ± 2 sec; n = 3) than functional recovery, indicating that desensitized receptors need not be bound by GABA. These data provide direct evidence for a cyclical model of receptor desensitization.

KW - Affinity

KW - Binding

KW - Desensitization

KW - GABA receptor

KW - Kinetics

KW - Oocyte

UR - http://www.scopus.com/inward/record.url?scp=0037107163&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0037107163&partnerID=8YFLogxK

M3 - Article

C2 - 12223551

AN - SCOPUS:0037107163

VL - 22

SP - 7982

EP - 7990

JO - Journal of Neuroscience

JF - Journal of Neuroscience

SN - 0270-6474

IS - 18

ER -