Amacrine cells are the most diverse neurons in the retina. There are 30 or more morphologically distinct subtypes of amacrine cells. Most of the amacrine cells are inhibitory and modulate the signaling between the bipolar and the ganglion cells within the inner plexiform layer (IPL).
GABAergic amacrine cells rely on the GABA neurotransmitter. These wide- and medium-field neurons project to individual sublaminae of the IPL and mediate lateral interactions that shape the receptive fields of the ganglion cells. GABAergic amacrine cells can be subdivided into smaller subsets of cells, characterized by their profiles of expressed neurotransmitter and transcription factor markers. This classification includes the dopaminergic, the starburst cholinergic and the displaced amacrine cells in the ganglion cell layer.