Abstract
Network properties of gap junction connections between retinal amacrine cells in the inner plexiform layer were evaluated by techniques of microelectrode- or patch clamp- recording, intracellular labeling and electron microscopy. First, amacrine cells were examined with their light-evoked responses to light flashes. Second, cells' voltage-responses against current injection were characterized. Third, coupled networks of the cell populations were visualized by transfer of intracellularly injected Neurobiotin into neighbors. Contacts between amacrine cells were then investigated with high voltage as well as conventional electron microscopy. Cell-type specific, homotypic dendrodendritic connections in the populations were found. Ultrastructural analysis revealed the presence of gap junctions between light-microscopically documented dendritic contact sites, but not in dendrites apart from interconnected sites. These results demonstrate that gap junction connections between amacrine cells are in homotypical manner. Electrophysiological properties of their homotypic gap junctions provide that these amacrine cells can take an advantage in performing lateral interaction in the inner plexiform layer. [Jpn J Physiol 54 Suppl:S163 (2004)]
