Abstract
Purpose: :
Retinal horizontal cells are connected to eachother by gap-junctions. In the zebrafish retina Cx55.5 and Cx52.6 have been shown to be present in gap-junctions between horizontal cells. Eastman et al., (2006) distinguished a special group of connexins in the range of 50 to 60 kD. The zebrafish Cx52.7 and Cx52.9 belongs to this group. The aim of this study is to determine whether these two Cx’s are involved in gap-junction formation between horizontal cells as well.
Methods: :
Chicken antibodies were raised against Cx52.7 and Cx52.9. Zebrafish retinas were fixed in 4% pfa and 1% carbodiimide and incubated with antibodies against zebrafish Cx52.7 and Cx52.9. Standard immunofluorensence was performed.
Results: :
Tyrosine hydroxylase positive terminals are innervating horizontal somata. Punctate labeling of Cx52.7 and Cx 52.9 were observed at the same level of tyrosine hydroxylase immunoreactivity; demonstrating that Cx52.7 and Cx52.9 are at the level of the horizontal cells in the zebrafish retina. Double label experiments with Cx55.5 resulted in colocalization with Cx52.7 and Cx52.9. Also double label experiments with Cx52.6 and Cx52.7 and Cx52.9 result in colocalization.
Keywords: horizontal cells • gap junctions/coupling • retina: distal (photoreceptors, horizontal cells, bipolar cells)