L-Glutamate-induced responses in OFF-type bipolar cells of the cat retina.
L-Glutamate (Glu)-induced current responses were studied in 119 isolated OFF-type bipolar cells of the cat retina. Cells were recorded by the patch clamp technique in the whole-cell configuration. Glu induced a current carried by alkali metal ions and divalent cations with a permeability ratio of PNa:PK:PCs:PCa = 1:0.94:1.32:0.57. Sensitivity to Glu was highest in the dendritic region. Kainate and AMPA worked as potent agonists, but neither APB, L-aspartate, ACPD, nor NMDA (all at 100 microM) was effective. The Glu-induced response was antagonized by > 1 microM CNQX. We inferred that OFF-type bipolar cells have a non-NMDA receptor channel that is permeable to alkali metal ions with low selectivity, but not NMDA receptor or metabotropic Glu receptor.
Sasaki
T
T
Department of Physiology, Keio University School of Medicine, Tokyo, Japan.
Kaneko
A
A
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000613:Aminobutyrates / Q000494:pharmacology; D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002415:Cats; D002712:Chlorides / Q000378:metabolism; D003515:Cycloleucine / Q000031:analogs & derivatives / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D018698:Glutamic Acid / Q000494:pharmacology*; D005998:Glycine / Q000494:pharmacology; D066298:In Vitro Techniques; D017136:Ion Transport / Q000187:drug effects; D007608:Kainic Acid / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D016202:N-Methylaspartate / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism; D012160:Retina / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology; D012964:Sodium / Q000378:metabolism; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
D000613:Aminobutyrates; D002712:Chlorides; D003515:Cycloleucine; C036361:1-amino-1,3-dicarboxycyclopentane; D001224:Aspartic Acid; D018698:Glutamic Acid; D016202:N-Methylaspartate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D012964:Sodium; C012729:2-amino-4-phosphonobutyric acid; D011188:Potassium; D007608:Kainic Acid; D002118:Calcium; D005998:Glycine