title: Responses of rod bipolar cells isolated from the rat retina to the glutamate agonist 2-amino-4-phosphonobutyric acid (APB).
abstract: Isolated rod bipolar cells were obtained by enzymatic (papain) and mechanical dissociation of the adult rat retina. Virtually all intact bipolar cells in the dissociates expressed protein kinase C (PKC) immunoreactivity, a selective marker for rod bipolar cells in the in vivo retina. Whole-cell recordings were performed using nystatin in the patch pipette to minimize washout of those cytoplasmic components necessary for the maintenance of ionic currents. At holding potentials of -33 mV, a tonic inward current was observed. The glutamate agonist 2-amino-4-phosphonobutyrate (APB) reduced this current by closing ion channels. Under normal conditions, Na+ appeared to be the main charge carrier. Both the internal and the external Ca2+ concentrations were found to exert a powerful influence on the APB-sensitive current. We conclude that the rod bipolar cell in situ is depolarized at light onset.
authors.affiliation: Max-Planck-Institut für Hirnforschung, Frankfurt, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Yamashita
authors.forename: H
authors.initials: H
authors.lastname: Wässle
mesh_terms: D000613:Aminobutyrates / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000494:pharmacology / Q000502:physiology; D002352:Carrier Proteins / Q000502:physiology; D002469:Cell Separation; D004553:Electric Conductivity; D004594:Electrophysiology; D005971:Glutamates / Q000502:physiology*; D018698:Glutamic Acid; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism; D010786:Photoreceptor Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D011493:Protein Kinase C / Q000502:physiology; D051381:Rats; D019831:Sodium-Calcium Exchanger
chemical_list: D000613:Aminobutyrates; D002352:Carrier Proteins; D005971:Glutamates; D007473:Ion Channels; D019831:Sodium-Calcium Exchanger; D018698:Glutamic Acid; D011493:Protein Kinase C; C012729:2-amino-4-phosphonobutyric acid; D002118:Calcium