Differential Effects of Ethanol on GABAA and Glycine Receptor-Mediated Synaptic Currents in Brain Stem Motoneurons
Department of Physiology and Biophysics, School of Medicine, University of Washington, Seattle, Washington 98195-7290 Submitted 7 February 2003; accepted in final form 4 April 2003 Ethanol potentiates glycinergic synaptic transmission to hypoglossal motoneurons (HMs). This effect on glycinergic tran...
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Published in | Journal of neurophysiology Vol. 90; no. 2; p. 870 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Am Phys Soc
01.08.2003
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Online Access | Get full text |
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Summary: | Department of Physiology and Biophysics, School of Medicine, University
of Washington, Seattle, Washington 98195-7290
Submitted 7 February 2003;
accepted in final form 4 April 2003
Ethanol potentiates glycinergic synaptic transmission to hypoglossal
motoneurons (HMs). This effect on glycinergic transmission changes with
postnatal development in that juvenile HMs (P913) are more sensitive to
ethanol than neonate HMs (P13). We have now extended our previous study
to investigate ethanol modulation of synaptic GABA A receptors
(GABA A Rs), because both GABA and glycine mediate inhibitory
synaptic transmission to brain stem motoneurons. We tested the effects of
ethanol on GABAergic and glycinergic miniature inhibitory postsynaptic
currents (mIPSCs) recorded from neonate and juvenile rat HMs in an in vitro
slice preparation. Bath application of 30 mM ethanol had no significant effect
on the GABAergic mIPSC amplitude or frequency recorded at either age. At 100
mM, ethanol significantly decreased the GABAergic mIPSC amplitude recorded
from neonate (6 ± 3%, P < 0.05) and juvenile (16 ±
3%, P < 0.01) HMs. The same concentration of ethanol increased the
GABAergic mIPSC frequency recorded from neonate (64 ± 17%, P
< 0.05) and juvenile (40 ± 15%, n.s.) HMs. In contrast, 100 mM
ethanol robustly potentiated glycinergic mIPSC amplitude in neonate (31
± 3%, P < 0.0001) and juvenile (41 ± 7%, P
< 0.001) HMs. These results suggest that glycine receptors are more
sensitive to modulation by ethanol than GABA A receptors and that
100 mM ethanol has the opposite effect on GABA A R-mediated currents
in juvenile HMs, that is, inhibition rather than enhancement. Further,
comparing ethanol's effects on GABAergic mIPSC amplitude and frequency,
ethanol modulates GABAergic synaptic transmission to HMs differentially.
Presynaptically, ethanol enhances mIPSC frequency while postsynaptically it
decreases mIPSC amplitude.
Address for reprint requests: J. Y. Sebe, Department of Physiology and
Biophysics, School of Medicine, University of Washington, Box 357290, Seattle,
WA 98195-7290 (E-mail:
sebe{at}u.washington.edu ). |
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ISSN: | 0022-3077 1522-1598 |
DOI: | 10.1152/jn.00119.2003 |