Acetylcholine (ACh) affects the response properties of many retinal ganglion cells (GCs) through the activation of
nicotinic acetylcholine receptors (nAChRs). To date there have been few studies directly correlating the expression of specific nAChR subtypes with the physiological and morphological characteristics of specific
retinal GCs. This study was designed to correlate responses to
nicotine application with immunohistochemical evidence of nAChR expression in physiologically and morphologically identified
ganglion cells. Extracellular recordings were used to physiologically identify rabbit
retinal GCs, based on responses to light stimulation. Cells were then tested for responses to
nicotine application and/or for expression of nAChRs, as judged by immunoreactivity to mAb210, an nAChR antibody. The morphologies of many physiologically identified cells were also determined by
dye injection. More than three-fourths of
ganglion cells tested responded to
nicotine application under
cobalt-induced synaptic blockade. The
nicotine sensitivity was consistent with nAChR immunoreactivity and was also correlated with specific morphological subgroups of GCs. Overall, approximately two-thirds of all physiologically identified GCs that were processed for immunohistochemistry displayed immunoreactivity. In total, 18 of 22 physiologically identified cells demonstrated both sensitivity to
nicotine application under synaptic blockade and mAb210 immunoreactivity (mAb210-IR). Thus, mAb210-IR is likely to represent functional nAChRs that can modulate
retinal information processing and visual functioning via direct excitation of a number of GC classes.