White perch horizontal cells in culture: methods, morphology and process growth.

Four types of horizontal cells are recognized in primary cultures of the adult white perch retina. Immediately after isolation, all horizontal cell types show fine terminal processes. However, these fine processes disappear over the next 12-24 h and the cells typically round up partially. After 2-4 days in culture, new processes appear on the horizontal cells, and these usually grow substantially with time. By 14-21 days, processes several hundred micrometers in length are observed in the retinal culture dishes. Processes from different cells intertwine and contacts that appear synaptic in nature are observed.