Direct electrical connections between transient amacrine cells in the catfish retina.

Transient amacrine cells were identified by their intracellularly recorded response to flashes of light. These cells typically respond with a transient depolarization, often followed by a steady-state response during the stimulus. When two electrodes were placed in different transient amacrine cells, current of either polarity passed through one electrode produced a steady-state voltage change that was recorded by the electrode in the nearby cell. Following identification of the physiological type, transient amacrine cells were injected with horseradish peroxidase and the tissue was processed for light and electron microscopy. Both conventional chemical synaptic junctions and gap junctions were found to connect amacrine cells.