Glutamate receptors differ in rod- and cone-dominated off-center bipolar cells.
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.
Maple
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Cullen Eye Institute, Baylor College of Medicine, Houston, TX 77030, USA.
Gao
F
F
Wu
S M
SM
D000557:Ambystoma; D000818:Animals; D001369:Axons / Q000187:drug effects / Q000378:metabolism; D001581:Benzothiadiazines / Q000494:pharmacology; D048429:Cell Size; D003712:Dendrites / Q000187:drug effects / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D004553:Electric Conductivity; D005074:Evoked Potentials, Visual / Q000187:drug effects / Q000502:physiology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D018698:Glutamic Acid / Q000494:pharmacology; D066298:In Vitro Techniques; D007814:Larva; D010775:Photic Stimulation; D018091:Receptors, AMPA / Q000378:metabolism*; D017949:Retinal Cone Photoreceptor Cells / Q000033:anatomy & histology / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D017948:Retinal Rod Photoreceptor Cells / Q000033:anatomy & histology / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D013569:Synapses / Q000187:drug effects / Q000378:metabolism; D014795:Visual Pathways / Q000033:anatomy & histology / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism
D001581:Benzothiadiazines; D018091:Receptors, AMPA; D018698:Glutamic Acid; C004639:cyclothiazide