The coexistence of two neuroactive peptides in a subpopulation of retinal amacrine cells

Amacrine cells are axonless interneurons of the vertebrate retina. Over the past few years many neuroactive peptides have been localized to these cells. We have previously demonstrated that a neuropeptide and a classical transmitter are colocalized in some amacrine cells. In this report, we show that two neuroactive peptides, which probably arise from different precursors, also coexist in some amacrine cells. Although some amacrine cells contain only enkephalin or neurotensin, others contain both of these neuroactive peptides.