Abstract
Synaptic transmission between dendrites in the olfactory bulb is thought to play a major role in the processing of olfactory information. Glutamate released from mitral cell dendrites excites the dendrites of granule cells, which in turn mediate GABAergic dendrodendritic inhibition back onto mitral dendrites. We examined the mechanisms governing reciprocal dendritic transmission in rat olfactory bulb slices. We find that NMDA receptors play a critical role in this dendrodendritic inhibition. As with axonic synapses, the dendritic release of fast neurotransmitters relies on N- and P/Q-type calcium channels. The magnitude of dendrodendritic transmission is directly proportional to dendritic calcium influx. Furthermore, recordings from pairs of mitral cells show that dendrodendritic synapses can mediate lateral inhibition independently of axonal action potentials.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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2-Amino-5-phosphonovalerate / pharmacology
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Animals
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Axons / physiology
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Calcium / metabolism
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Calcium Channel Blockers / pharmacology
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Calcium Channels / drug effects
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Calcium Channels / physiology*
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Dendrites / drug effects
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Dendrites / physiology*
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Excitatory Postsynaptic Potentials / drug effects
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Excitatory Postsynaptic Potentials / physiology*
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Glycine / pharmacology
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In Vitro Techniques
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Models, Neurological
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Nifedipine / pharmacology
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Olfactory Bulb / physiology*
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Patch-Clamp Techniques
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Peptides / pharmacology
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Quinoxalines / pharmacology
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Rats
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Rats, Sprague-Dawley
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Receptors, N-Methyl-D-Aspartate / physiology
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Signal Transduction / physiology*
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Synapses / drug effects
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Synapses / physiology*
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Synaptic Transmission / drug effects
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Synaptic Transmission / physiology*
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Tetrodotoxin / pharmacology
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omega-Conotoxin GVIA
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omega-Conotoxins*
Substances
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Calcium Channel Blockers
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Calcium Channels
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Peptides
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Quinoxalines
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Receptors, N-Methyl-D-Aspartate
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omega-Conotoxins
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omega-conotoxin-MVIIC
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Tetrodotoxin
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FG 9041
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2-Amino-5-phosphonovalerate
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omega-Conotoxin GVIA
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Nifedipine
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Calcium
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Glycine