Abstract
Signal transmission from a chick hair cell to the growth cone of a vestibular ganglion cell was examined by placing an acutely dissociated hair cell on the growth cone of a cultured vestibular ganglion cell. Electrical stimuli were applied to the hair cell while monitoring the intracellular Ca(2+) concentration ([Ca(2+)](i)) at the growth cone or recording whole-cell currents from the vestibular ganglion cell. Electrical stimulation of the hair cell induced [Ca(2+)](i) increases at the growth cone and inward currents in the vestibular ganglion cell. The [Ca(2+)](i) increase was blocked by 6-cyano-7-nitroquinoxaline (CNQX) (10 microM) but not by 2-amino-5-phosphonovaleric acid (APV; 50 microM). Glutamate (100 nM-300 microM) applied to the vestibular ganglion cell by the Y-tube method induced inward currents which were also antagonized by CNQX, but not by APV. These results indicate that the electrical stimulation of a hair cell induced glutamate or glutamate like agent release from the hair cell, which activated non-N-methyl-D-aspartate receptors at the growth cone of the vestibular ganglion cell, followed by action potentials and [Ca(2+)](i) elevation in the vestibular ganglion cell. This is the first demonstration of in vitro reconstitution of functional signal transmission from a hair cell to a vestibular ganglion cell.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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6-Cyano-7-nitroquinoxaline-2,3-dione / pharmacology
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Animals
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Animals, Newborn
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Calcium / metabolism
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Cells, Cultured
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Chick Embryo
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Dose-Response Relationship, Drug
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Electric Stimulation
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Evoked Potentials / drug effects
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Evoked Potentials / physiology
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Excitatory Amino Acid Antagonists / pharmacology
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Fura-2 / analogs & derivatives*
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Fura-2 / metabolism
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Ganglia, Sensory / cytology
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Ganglia, Sensory / drug effects
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Ganglia, Sensory / metabolism
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Ganglia, Sensory / physiology*
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Glutamic Acid / pharmacology
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Growth Cones / drug effects
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Growth Cones / metabolism
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Growth Cones / physiology*
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Hair Cells, Vestibular / drug effects
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Hair Cells, Vestibular / metabolism
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Hair Cells, Vestibular / physiology*
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Hippocampus / cytology
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Hippocampus / drug effects
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Hippocampus / metabolism
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Immunohistochemistry
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In Vitro Techniques
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Neural Conduction / drug effects
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Patch-Clamp Techniques
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Rats
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Rats, Wistar
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Receptors, AMPA / metabolism
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Signal Transduction / physiology*
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Time Factors
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Valine / analogs & derivatives*
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Valine / pharmacology
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Vestibule, Labyrinth / cytology
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Vestibule, Labyrinth / drug effects
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Vestibule, Labyrinth / metabolism
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Vestibule, Labyrinth / physiology*
Substances
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Excitatory Amino Acid Antagonists
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Receptors, AMPA
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glutamate receptor ionotropic, AMPA 3
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fura-2-am
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Glutamic Acid
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6-Cyano-7-nitroquinoxaline-2,3-dione
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2-amino-5-phosphopentanoic acid
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Valine
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glutamate receptor ionotropic, AMPA 2
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Calcium
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Fura-2