In this thesis, the search for candidate proteins contributing to the feedback mechanism between horizontal cells and cones in the zebrafish retina revealed that the zebrafish genome encodes for two pannexin 1 proteins, zfPanx1 and zfPanx1-similar.
Both are expressed in the CNS including the retina, where zfPanx1 is located at the tip of horizontal cell dendrites in the cone synaptic complex, suggesting a role of zfPanx1 in the stated feedback pathway. zfPanx1 and zfPanx1-similar are glycoproteins,
forming active membrane channels that can be modulated by intracellular Ca2+, pH and ATP. Structure-function analyses revealed critical roles of transmembrane cysteine residues. Despite several
similarities, electrophysiological recordings showed distinct biophysical channel properties. This thesis provides a significant contribution to the better understanding of the role of Panx1 under physiological and pathophysiological conditions, with a
particular focus on the retina.