Organization of Catecholaminergic Amacrine Cells in the Rhesus Monkey Retina

Abstract

Dopamine-containing amacrine cells were among the first of many different neurotransmitter phenotypes identified in the macaque retina owing to their blue-green, formaldehyde-induced fluorescence (Ehinger, 1966; Laties and Jacobowitz, 1966). They are neurons with cell bodies in the innermost row of the inner nuclear layer, processes that arborize in the outermost stratum of the inner plexiform layer, and fine, radially oriented fibers that course in the inner nuclear layer (see Figure 10.1A), and have been well-characterized with regard to their morphology (Nguyen-Legros et al., 1984), distribution across the retina (Mariani et al., 1984), and synaptic organization (Hokoç and Mariani, 1987). Although the appearance of dopaminergic neurons varies somewhat between species (Ehinger, 1982), there was, with the exception of perhaps two or three vertebrate species (Hadjiconstantinou et al., 1984; Keyser et al., 1987), little evidence for morphological variability among this transmitter phenotype in a single retina, including the rhesus monkey’s.