Nr. 3/1940] B r e d e r e c k , B e r g e r , Ehrenberg. 269 Dann wiirden die in Kap. 5 beschriebenen Versuche zu ganz anderen Erfolgen *) XIV. Mitteil.: B. 72, 1429 [1939]. l ) H. Bredereck u. G. Caro, Dtsch. Reichs-Pat. 653258 (4. 12. 1936). *) Biochem. Ztschr. 292, 356 [1937]. 9) H. Bredereck, Ztschr. physiol. Chem. 223, 61 [1934]. 4, Die nur amorph erhaltene Verbindung enthalt gleichzeitig noch Triacetyl-trityladenosin, wobei die dritte Acetylgruppe an der NH,-Gruppe sitzt. Dafiir spricht die Acetylbestimmung: Ber. 14.5 % fur die Diacetylverb. 20.3 % fiir die Triacetylverb. G f . 16.2 %. 1 8 '

Complexins (Cplxs) 1 to 4 are components of the presynaptic compartment of chemical synapses where they regulate important steps in synaptic vesicle exocytosis. In the retina, all four Cplxs are present, and while we know a lot about Cplxs 3 and 4, little is known about Cplxs 1 and 2. Here, we performed in situ hybridization experiments and bioinformatics and exploited Cplx 1 and Cplx 2 single-knockout mice combined with immunocytochemistry and light microscopy to characterize in detail the cell type and synapse-specific distribution of Cplx 1 and Cplx 2. We found that Cplx 2 and not Cplx 1 is the main isoform expressed in normal and displaced amacrine cells and ganglion cells in mouse retinae and that amacrine cells seem to operate with a single Cplx isoform at their conventional chemical synapses. Surprising was the finding that retinal function, determined with electroretinographic recordings, was altered in Cplx 1 but not Cplx 2 single-knockout mice. In summary, the results provide an important basis for future studies on the function of Cplxs 1 and 2 in the processing of visual signals in the mammalian retina.