N-ethylmaleimide blocks depolarization-induced suppression of inhibition and enhances GABA release in the rat hippocampal slice in vitro

Wade Morishita, Sergei A Kirov, Thomas A. Pitler, Laura A. Martin, Robert A. Lenz, Bradley E. Alger

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

Regulation of synaptic, GABA(A) receptor-mediated inhibition is a process of critical importance to normal brain function. Recently, we have described a phenomenon in hippocampus of a transient, yet marked, decrease in spontaneous, GABA(A) receptor-mediated IPSCs after depolarization activated Ca2+ influx into a pyramidal cell. This process, depolarization-induced suppression of inhibition (DSI), is absent in hippocampal cells that previously had been exposed to pertussis toxin in vivo, implicating a G- protein in the DSI process. To circumvent the problem that a single cell cannot be studied before and after G-protein block using the pertussis toxin pretreatment method, we have used the sulfhydryl alkylating agent N- ethylmaleimide (NEM), which blocks pertussis toxin-sensitive G-proteins, to determine whether acute inhibition of G-proteins can eliminate DSI of spontaneous IPBCs (sIPSCs). In whole-cell recordings from CA1 pyramidal cells that were first determined to express DSI, we have found that NEM does block DSI of sIPSCs. We also report that DSI of monosynaptic, evoked IPSCs is blocked by NEM, suggesting that a similar mechanism underlies both forms of DSI. It was of interest that DSI was abolished at a time when NEM had increased, not decreased, GABA transmission. Indeed, NEM greatly increased quantal GABA release by a Ca2+-independent mechanism, an observation with potentially important implications for understanding synaptic GABA release.

Original languageEnglish (US)
Pages (from-to)941-950
Number of pages10
JournalJournal of Neuroscience
Volume17
Issue number3
StatePublished - Feb 1 1997
Externally publishedYes

Fingerprint

Ethylmaleimide
gamma-Aminobutyric Acid
GTP-Binding Proteins
Pertussis Toxin
Pyramidal Cells
GABA-A Receptors
Alkylating Agents
Patch-Clamp Techniques
Hippocampus
Observation
In Vitro Techniques
Brain

Keywords

  • GABA
  • hippocampus
  • IPSC
  • mIPSCs
  • NEM
  • transmitter release

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

N-ethylmaleimide blocks depolarization-induced suppression of inhibition and enhances GABA release in the rat hippocampal slice in vitro. / Morishita, Wade; Kirov, Sergei A; Pitler, Thomas A.; Martin, Laura A.; Lenz, Robert A.; Alger, Bradley E.

In: Journal of Neuroscience, Vol. 17, No. 3, 01.02.1997, p. 941-950.

Research output: Contribution to journalArticle

Morishita, Wade ; Kirov, Sergei A ; Pitler, Thomas A. ; Martin, Laura A. ; Lenz, Robert A. ; Alger, Bradley E. / N-ethylmaleimide blocks depolarization-induced suppression of inhibition and enhances GABA release in the rat hippocampal slice in vitro. In: Journal of Neuroscience. 1997 ; Vol. 17, No. 3. pp. 941-950.
@article{303733c043c349628c7ec93b759f9b9f,
title = "N-ethylmaleimide blocks depolarization-induced suppression of inhibition and enhances GABA release in the rat hippocampal slice in vitro",
abstract = "Regulation of synaptic, GABA(A) receptor-mediated inhibition is a process of critical importance to normal brain function. Recently, we have described a phenomenon in hippocampus of a transient, yet marked, decrease in spontaneous, GABA(A) receptor-mediated IPSCs after depolarization activated Ca2+ influx into a pyramidal cell. This process, depolarization-induced suppression of inhibition (DSI), is absent in hippocampal cells that previously had been exposed to pertussis toxin in vivo, implicating a G- protein in the DSI process. To circumvent the problem that a single cell cannot be studied before and after G-protein block using the pertussis toxin pretreatment method, we have used the sulfhydryl alkylating agent N- ethylmaleimide (NEM), which blocks pertussis toxin-sensitive G-proteins, to determine whether acute inhibition of G-proteins can eliminate DSI of spontaneous IPBCs (sIPSCs). In whole-cell recordings from CA1 pyramidal cells that were first determined to express DSI, we have found that NEM does block DSI of sIPSCs. We also report that DSI of monosynaptic, evoked IPSCs is blocked by NEM, suggesting that a similar mechanism underlies both forms of DSI. It was of interest that DSI was abolished at a time when NEM had increased, not decreased, GABA transmission. Indeed, NEM greatly increased quantal GABA release by a Ca2+-independent mechanism, an observation with potentially important implications for understanding synaptic GABA release.",
keywords = "GABA, hippocampus, IPSC, mIPSCs, NEM, transmitter release",
author = "Wade Morishita and Kirov, {Sergei A} and Pitler, {Thomas A.} and Martin, {Laura A.} and Lenz, {Robert A.} and Alger, {Bradley E.}",
year = "1997",
month = "2",
day = "1",
language = "English (US)",
volume = "17",
pages = "941--950",
journal = "Journal of Neuroscience",
issn = "0270-6474",
publisher = "Society for Neuroscience",
number = "3",

}

TY - JOUR

T1 - N-ethylmaleimide blocks depolarization-induced suppression of inhibition and enhances GABA release in the rat hippocampal slice in vitro

AU - Morishita, Wade

AU - Kirov, Sergei A

AU - Pitler, Thomas A.

AU - Martin, Laura A.

AU - Lenz, Robert A.

AU - Alger, Bradley E.

PY - 1997/2/1

Y1 - 1997/2/1

N2 - Regulation of synaptic, GABA(A) receptor-mediated inhibition is a process of critical importance to normal brain function. Recently, we have described a phenomenon in hippocampus of a transient, yet marked, decrease in spontaneous, GABA(A) receptor-mediated IPSCs after depolarization activated Ca2+ influx into a pyramidal cell. This process, depolarization-induced suppression of inhibition (DSI), is absent in hippocampal cells that previously had been exposed to pertussis toxin in vivo, implicating a G- protein in the DSI process. To circumvent the problem that a single cell cannot be studied before and after G-protein block using the pertussis toxin pretreatment method, we have used the sulfhydryl alkylating agent N- ethylmaleimide (NEM), which blocks pertussis toxin-sensitive G-proteins, to determine whether acute inhibition of G-proteins can eliminate DSI of spontaneous IPBCs (sIPSCs). In whole-cell recordings from CA1 pyramidal cells that were first determined to express DSI, we have found that NEM does block DSI of sIPSCs. We also report that DSI of monosynaptic, evoked IPSCs is blocked by NEM, suggesting that a similar mechanism underlies both forms of DSI. It was of interest that DSI was abolished at a time when NEM had increased, not decreased, GABA transmission. Indeed, NEM greatly increased quantal GABA release by a Ca2+-independent mechanism, an observation with potentially important implications for understanding synaptic GABA release.

AB - Regulation of synaptic, GABA(A) receptor-mediated inhibition is a process of critical importance to normal brain function. Recently, we have described a phenomenon in hippocampus of a transient, yet marked, decrease in spontaneous, GABA(A) receptor-mediated IPSCs after depolarization activated Ca2+ influx into a pyramidal cell. This process, depolarization-induced suppression of inhibition (DSI), is absent in hippocampal cells that previously had been exposed to pertussis toxin in vivo, implicating a G- protein in the DSI process. To circumvent the problem that a single cell cannot be studied before and after G-protein block using the pertussis toxin pretreatment method, we have used the sulfhydryl alkylating agent N- ethylmaleimide (NEM), which blocks pertussis toxin-sensitive G-proteins, to determine whether acute inhibition of G-proteins can eliminate DSI of spontaneous IPBCs (sIPSCs). In whole-cell recordings from CA1 pyramidal cells that were first determined to express DSI, we have found that NEM does block DSI of sIPSCs. We also report that DSI of monosynaptic, evoked IPSCs is blocked by NEM, suggesting that a similar mechanism underlies both forms of DSI. It was of interest that DSI was abolished at a time when NEM had increased, not decreased, GABA transmission. Indeed, NEM greatly increased quantal GABA release by a Ca2+-independent mechanism, an observation with potentially important implications for understanding synaptic GABA release.

KW - GABA

KW - hippocampus

KW - IPSC

KW - mIPSCs

KW - NEM

KW - transmitter release

UR - http://www.scopus.com/inward/record.url?scp=0031027842&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0031027842&partnerID=8YFLogxK

M3 - Article

C2 - 8994049

AN - SCOPUS:0031027842

VL - 17

SP - 941

EP - 950

JO - Journal of Neuroscience

JF - Journal of Neuroscience

SN - 0270-6474

IS - 3

ER -