Reproducing retinal rod bipolar cell light response by mathematical model including neurotransmitter receptors.

Detailed mathematical model of retinal cells is useful for the quantitative understanding of the subcellular processes of the visual system. Retinal bipolar cells receive information from photoreceptor cells, horizontal cells and amacrine cells, thus it can be considered as information integration system. Despite its importance, bipolar cell model including inputs and outputs has not been proposed. In this paper, we propose a rod bipolar cell model which can reproduce voltage response of light. The model includes TRPM1 channel which receives signal from photoreceptor cells, GABA channel which receives signal from surrounding amacrine cells, and cell body model which is based on the model proposed by Ishihara et al. The model was evaluated with several light signals, where experimentally obtained photoreceptor cell responses were used as TRPM1 channel input. Resulting bipolar cell membrane potential showed good agreement with the reported experimental results.