TY - JOUR T1 - Glutamate Responses of Bipolar Cells in a Slice Preparation of the Rat Retina JF - The Journal of Neuroscience JO - J. Neurosci. SP - 2934 LP - 2944 DO - 10.1523/JNEUROSCI.16-09-02934.1996 VL - 16 IS - 9 AU - Thomas Euler AU - Horst Schneider AU - Heinz Wässle Y1 - 1996/05/01 UR - http://www.jneurosci.org/content/16/9/2934.abstract N2 - Whole-cell currents from >70 voltage-clamped bipolar cells were recorded in a slice preparation of the rat retina. The recorded cells were identified and classified by intracellular staining with Lucifer yellow. Glutamate, the specific agonists (±)-2-amino-4-phosphonobutyric acid (AP-4) and kainate (KA), and the antagonist 6-cyanoquinoxaline-2,3-dione (CNQX) were applied. The cells could be isolated from presynaptic influences by the co-application of bicuculline, strychnine, and cobalt ions. Responses to AP-4 were elicited only from bipolar cells with axons stratifying in the inner part of the inner plexiform layer (IPL). AP-4 caused an outward current in these cells attributable to the closure of nonspecific cation channels. Responses to kainate representing a direct action of the drug on the recorded cells were observed only in bipolar cells with axons stratifying in the outer part of the IPL. KA caused a CNQX-sensitive inward current in these cells, associated with openings of nonspecific cation channels. The results predict that cone bipolar (CB) cells with axons terminating in the outer IPL are OFF-bipolars, whereas those with axons terminating in the inner IPL are ON-bipolars. Most of the cells expressed GABA-gated Cl− conductances. In rod bipolar and in some CB cells, only part of the GABA-induced currents could be blocked by the application of bicuculline, suggesting the presence of GABAC receptors in addition to GABAAreceptors. ER -