Dendritic morphology of dopaminergic cells revealed by intracellular injection of Lucifer yellow in fixed carp retina.

The dendritic morphology of dopaminergic cells in carp retinas was investigated by identifying their fluorescent cell bodies in isolated, aldehyde-fixed preparations and injecting them iontophoretically with Lucifer yellow CH (LY) under microscopic control. The LY-injected cells were examined in flatmount and in radial cryosections. The cell bodies were located at the inner margin of the inner nuclear layer (the amacrine cell sublayer), and gave rise to 3-5 primary dendrites that branched repeatedly within the inner plexiform layer to form a narrow-field, diffusely branched dendritic tree. In some cases, a distal process was found to extent to the outer plexiform layer, representing the interplexiform type of cells. The 59 filled cells had roughly round or oval dendritic fields covering an area of 0.102 +/- 0.003 mm2 (361 +/- 57 micron in diameter) in the intermediate retinal region. The density of dopaminergic cells in this region was 31 cells/mm2 and, therefore, the dendritic field coverage of these cells approximately 3.0.