Abstract
Mossy fiber synaptic transmission at hippocampal CA3 pyramidal cells and interneurons was compared in rat brain slices to determine whether mossy terminals are functionally equivalent. Tetanic stimulation of mossy fibers induced long-term potentiation in pyramidal neurons but was either without effect or it induced depression at synapses onto interneurons. Unlike transmission onto pyramidal neurons, transmission onto interneurons was not potentiated after adenosine 3',5'-monophosphate (cAMP) activation. Furthermore, metabotropic glutamate receptor depression of transmission onto interneurons did not involve cAMP-dependent pathways. Thus, synaptic terminals arising from a common afferent pathway do not function as a single compartment but are specialized, depending on their postsynaptic target.
Publication types
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Comparative Study
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Afferent Pathways
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Animals
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Colforsin / pharmacology
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Cyclic AMP / metabolism
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Cycloleucine / analogs & derivatives
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Cycloleucine / pharmacology
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Cyclopropanes / pharmacology
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Electric Stimulation
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Excitatory Postsynaptic Potentials / drug effects
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Glycine / analogs & derivatives
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Glycine / pharmacology
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Hippocampus / cytology
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Hippocampus / physiology*
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In Vitro Techniques
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Interneurons / drug effects
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Interneurons / physiology*
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Long-Term Potentiation*
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Mossy Fibers, Hippocampal / physiology*
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Pyramidal Cells / drug effects
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Pyramidal Cells / physiology*
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Rats
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Rats, Sprague-Dawley
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Receptors, Metabotropic Glutamate / agonists
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Receptors, Metabotropic Glutamate / physiology
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Synaptic Transmission / drug effects
Substances
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Cyclopropanes
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Receptors, Metabotropic Glutamate
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Cycloleucine
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1-amino-1,3-dicarboxycyclopentane
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2-(2,3-dicarboxycyclopropyl)glycine
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Colforsin
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Cyclic AMP
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Glycine