GABAB receptor-mediated inhibition of spontaneous inhibitory synaptic currents in rat midbrain culture
1. Tight-seal, whole-cell recording was used to study GABAB receptor-mediated inhibition of spontaneous inhibitory synaptic currents in cultured rat midbrain neurones. 2. Spontaneous miniature inhibitory postsynaptic currents (mIPSCs) were recorded in tetrodotoxin (TTX), Cd2+ and Ba2+. (R)-(-)-baclo...
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Published in | The Journal of physiology Vol. 500; no. Pt 3; pp. 739 - 749 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
England
The Physiological Society
01.05.1997
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Subjects | |
Online Access | Get full text |
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Summary: | 1. Tight-seal, whole-cell recording was used to study GABAB receptor-mediated inhibition of spontaneous inhibitory synaptic
currents in cultured rat midbrain neurones. 2. Spontaneous miniature inhibitory postsynaptic currents (mIPSCs) were recorded
in tetrodotoxin (TTX), Cd2+ and Ba2+. (R)-(-)-baclofen reduced the frequency of mIPSCs through a presynaptic mechanism. The
EC50 for this effect was 7 microM. It was antagonized by the GABAB receptor antagonist CGP55845A (0.5 microM). 3. In pertussis
toxin (PTX)-treated cultures, some GABAB receptor-mediated reduction of the frequency of mIPSCs persisted. In contrast, PTX
treatment totally abolished inhibition of miniature excitatory postsynaptic currents (mEPSCs). 4. In PTX-treated cultures,
a saturating concentration of (R)-(-)-baclofen inhibited action potential-generated IPSCs but no EPSCs. 5. PTX treatment abolished
the (R)-(-)-baclofen-mediated inhibition of high voltage-activated somatic Ca2+ currents and of spontaneous IPSCs depending
on presynaptic Ca2+ entry. 6. We conclude that cellular mechanisms underlying GABAB receptor-mediated inhibition of mIPSCs
contribute to auto-inhibition of GABA release. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0022-3751 1469-7793 |
DOI: | 10.1113/jphysiol.1997.sp022055 |