Abstract
The axon morphology of off-center bipolar cells in salamander retinal slices was correlated with light responses and dendritic glutamate responses of these cells under voltage clamp. Cells with telodendria ramifying exclusively in the distal one-quarter of the inner plexiform layer were rod dominated, whereas cells with more centrally ramifying telodendria were cone dominated. The glutamate responses of the centrally ramifying cells displayed more apparent desensitization and a smaller underlying single channel conductance (1.2+/-0.3 pS) than did the distally ramifying cells (2.8+/-0.4 pS), although the responses for both classes of cells were strongly enhanced by cyclothiazide. These results suggest that different subtypes of AMPA receptors are present on rod- and cone-dominated cells, and that these may differ with respect to desensitization kinetics.
Publication types
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Comparative Study
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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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Ambystoma
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Animals
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Axons / drug effects
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Axons / metabolism
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Benzothiadiazines / pharmacology
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Cell Size
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Dendrites / drug effects
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Dendrites / metabolism
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Down-Regulation / drug effects
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Electric Conductivity
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Evoked Potentials, Visual / drug effects
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Evoked Potentials, Visual / physiology
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Excitatory Postsynaptic Potentials / drug effects
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Excitatory Postsynaptic Potentials / physiology
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Glutamic Acid / pharmacology
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In Vitro Techniques
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Larva
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Photic Stimulation
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Receptors, AMPA / metabolism*
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Retinal Cone Photoreceptor Cells / anatomy & histology
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Retinal Cone Photoreceptor Cells / cytology*
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Retinal Cone Photoreceptor Cells / drug effects
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Retinal Cone Photoreceptor Cells / physiology*
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Retinal Rod Photoreceptor Cells / anatomy & histology
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Retinal Rod Photoreceptor Cells / cytology*
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Retinal Rod Photoreceptor Cells / drug effects
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Retinal Rod Photoreceptor Cells / physiology*
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Synapses / drug effects
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Synapses / metabolism
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Visual Pathways / anatomy & histology
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Visual Pathways / cytology*
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Visual Pathways / drug effects
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Visual Pathways / metabolism
Substances
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Benzothiadiazines
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Receptors, AMPA
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Glutamic Acid
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cyclothiazide