A comparative study of protein kinase C-like immunoreactive cells in the retina

The present study is a morphological and quantitative analysis of protein k inase C-like immunoreactive (PKC-L-ir) bipolar cells in the retinas of five different vertebrate species (chicken, tench, zebrafish, goldfish and rat) . The morphology of PKC-L-ir bipolar cell axon terminals in fish differs si gnificantly from those of chicken and rat retinas. Fish have bulky terminal s whereas chicken and rat have their terminals in the form of small knob-sh aped branches. In tench and goldfish, PKC-L-ir bipolar cells gradually decr ease in size from the medial (i.e., in tench: mean +/- SD soma area of 30.0 9 +/- 5.98 mum(2)) to the peripheral (i.e., in tench: 19.93 +/- 1.73 mum(2) ) retinal regions. This is not observed in chicken, rat or zebrafish where there is more homogeneity in soma and axon terminal sizes between different retinal regions. Except in chicken, cell density increases from the centra l (i,e., in tench: mean i SD 1795.88 +/- 242.35 cells/mm(2)) to the periphe ral (i,e., in tench: 4295.41 +/- 279.23 cells/mm(2)) retina. This study pro vides data that show relevant differences in the PKC-L-ir bipolar morpholog y and density among birds, fish and mammals. Moreover, these structural var iations could mean not only differences in the cellular physiology, but als o in the patterns of development and maintenance of the retina in each spec ies. Copyright (C) 2001 S. Karger AG, Basel.