Abstract
The purpose of this study of GT1-7 neurons was to partially characterize basal Cl- transport and GABA(A) mediated Cl- efflux and to test the effect of ethanol on a GABA(A) receptor that lacks a γ subunit. We measured GABA(A) function and Cl- transport with 36C1-. Our results show that basel 36Cl- efflux varied with temperature at 4°C, 23°C, and 37°C. At 23°C, DIDS, an inhibitorof anion exchange, reduced basel 36Cl- efflux maximally by 79.6% with an IC50 of 42.1 μM, wheras burnetanide, an inhibitor of (Na-K-Cl) cotransport, had no effect on basal 36Cl- efflux at concentrations up to 150 μM. At 4°C, muscimol, a GABA(A) receptor agonist, stimulated 36Cl- efflux with an EC50 of 1.47 μM. Bicuculline, a GABA(A) receptor antagonist, completely reversed the effect of 20 μM muscimol with an IC50 of 6.08 μM. Ethanol, at concentrations up to 87 mM (0.4% (w/v)), had no effect on muscimol-induced 36Cl- efflux at 4°C or at 32°C. Our results indicate that stimulation of GABA(A) receptors causes an efflux of Cl- from GT1-7 neurons. This finding is consistent with the concept that stimulation of GABA(A) receptors produces depolarization of the plasma membrane, increase in cytosolic [Ca2+], and GnRH release. Our results represent the first description of chloride transport in GT1-7 neurons and suggest the presence of a Cl- exchange, but not (Na-K-Cl), transporter mechanism. Furthermore, the lack of an effect of ethanol observed in this study is consistent with the idea that a γ2L subunit may be necessary for the effects of low concentrations of ethanol at GABA(A) receptors.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 183-189 |
| Number of pages | 7 |
| Journal | Brain Research |
| Volume | 780 |
| Issue number | 2 |
| DOIs | |
| State | Published - Jan 12 1998 |
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Keywords
- Chloride
- Ethanol
- GABA(A)
- GnRH
- GT1-7
- Neuron
ASJC Scopus subject areas
- Neuroscience(all)
Cite this
Characterization of chloride efflux from GT1-7 neurons : Lack of effect of ethanol on GABA(A) response. / Javors, Martin A; King, Thomas S; Chang, Xiaoying; Ticku, Maharaj K.; Levinson, Charles.
In: Brain Research, Vol. 780, No. 2, 12.01.1998, p. 183-189.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Characterization of chloride efflux from GT1-7 neurons
T2 - Lack of effect of ethanol on GABA(A) response
AU - Javors, Martin A
AU - King, Thomas S
AU - Chang, Xiaoying
AU - Ticku, Maharaj K.
AU - Levinson, Charles
PY - 1998/1/12
Y1 - 1998/1/12
N2 - The purpose of this study of GT1-7 neurons was to partially characterize basal Cl- transport and GABA(A) mediated Cl- efflux and to test the effect of ethanol on a GABA(A) receptor that lacks a γ subunit. We measured GABA(A) function and Cl- transport with 36C1-. Our results show that basel 36Cl- efflux varied with temperature at 4°C, 23°C, and 37°C. At 23°C, DIDS, an inhibitorof anion exchange, reduced basel 36Cl- efflux maximally by 79.6% with an IC50 of 42.1 μM, wheras burnetanide, an inhibitor of (Na-K-Cl) cotransport, had no effect on basal 36Cl- efflux at concentrations up to 150 μM. At 4°C, muscimol, a GABA(A) receptor agonist, stimulated 36Cl- efflux with an EC50 of 1.47 μM. Bicuculline, a GABA(A) receptor antagonist, completely reversed the effect of 20 μM muscimol with an IC50 of 6.08 μM. Ethanol, at concentrations up to 87 mM (0.4% (w/v)), had no effect on muscimol-induced 36Cl- efflux at 4°C or at 32°C. Our results indicate that stimulation of GABA(A) receptors causes an efflux of Cl- from GT1-7 neurons. This finding is consistent with the concept that stimulation of GABA(A) receptors produces depolarization of the plasma membrane, increase in cytosolic [Ca2+], and GnRH release. Our results represent the first description of chloride transport in GT1-7 neurons and suggest the presence of a Cl- exchange, but not (Na-K-Cl), transporter mechanism. Furthermore, the lack of an effect of ethanol observed in this study is consistent with the idea that a γ2L subunit may be necessary for the effects of low concentrations of ethanol at GABA(A) receptors.
AB - The purpose of this study of GT1-7 neurons was to partially characterize basal Cl- transport and GABA(A) mediated Cl- efflux and to test the effect of ethanol on a GABA(A) receptor that lacks a γ subunit. We measured GABA(A) function and Cl- transport with 36C1-. Our results show that basel 36Cl- efflux varied with temperature at 4°C, 23°C, and 37°C. At 23°C, DIDS, an inhibitorof anion exchange, reduced basel 36Cl- efflux maximally by 79.6% with an IC50 of 42.1 μM, wheras burnetanide, an inhibitor of (Na-K-Cl) cotransport, had no effect on basal 36Cl- efflux at concentrations up to 150 μM. At 4°C, muscimol, a GABA(A) receptor agonist, stimulated 36Cl- efflux with an EC50 of 1.47 μM. Bicuculline, a GABA(A) receptor antagonist, completely reversed the effect of 20 μM muscimol with an IC50 of 6.08 μM. Ethanol, at concentrations up to 87 mM (0.4% (w/v)), had no effect on muscimol-induced 36Cl- efflux at 4°C or at 32°C. Our results indicate that stimulation of GABA(A) receptors causes an efflux of Cl- from GT1-7 neurons. This finding is consistent with the concept that stimulation of GABA(A) receptors produces depolarization of the plasma membrane, increase in cytosolic [Ca2+], and GnRH release. Our results represent the first description of chloride transport in GT1-7 neurons and suggest the presence of a Cl- exchange, but not (Na-K-Cl), transporter mechanism. Furthermore, the lack of an effect of ethanol observed in this study is consistent with the idea that a γ2L subunit may be necessary for the effects of low concentrations of ethanol at GABA(A) receptors.
KW - Chloride
KW - Ethanol
KW - GABA(A)
KW - GnRH
KW - GT1-7
KW - Neuron
UR - http://www.scopus.com/inward/record.url?scp=0032509739&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032509739&partnerID=8YFLogxK
U2 - 10.1016/S0006-8993(97)01134-7
DO - 10.1016/S0006-8993(97)01134-7
M3 - Article
C2 - 9507117
AN - SCOPUS:0032509739
VL - 780
SP - 183
EP - 189
JO - Brain Research
JF - Brain Research
SN - 0006-8993
IS - 2
ER -