TY - JOUR T1 - Responses of rod bipolar cells isolated from the rat retina to the glutamate agonist 2-amino-4-phosphonobutyric acid (APB) JF - The Journal of Neuroscience JO - J. Neurosci. SP - 2372 LP - 2382 DO - 10.1523/JNEUROSCI.11-08-02372.1991 VL - 11 IS - 8 AU - M Yamashita AU - H Wassle Y1 - 1991/08/01 UR - http://www.jneurosci.org/content/11/8/2372.abstract N2 - 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. ER -