Fig. 2.

Dark-adapted L-IPSCs are mostly mediated by glycinergic input in OFF1,2,4 but not OFF3 BCs. A and B: example L-IPSCs recorded from an OFF1/2 and an OFF3 BC, respectively, in response to a 30-ms flash of light (dark gray bar below L-IPSC). The dark-adapted L-IPSC was greatly reduced by application of strychnine. Recording paradigm is shown on left with glycine receptors blocked. C and D: intensity-response curves of normalized charge transfer of OFF1,2,4 (n = 6) and OFF3 (n = 4) BCs, respectively, to the max dark-adapted L-IPSCs. Strychnine significantly reduced OFF1,2,4 L-IPSCs at all light intensities, while only the 3 highest light intensities were reduced in OFF3 BCs. Glycinergic inhibition in OFF3 BCs appears to be a smaller component than in OFF1,2,4 BCs (P < 0.05). *P < 0.05, **P < 0.01.