GABAc receptor model of retinal horizontal cells simulating emphasis of light-dark contrast

We simulated the GABAc receptor model that has two functionally contrastive binding sites represented by Ca²⁺ (facilitation) and Zn²⁺ (inhibition) in the extracellular domain, and investigate the effect of GABAc receptors by extracellular Zn²⁺ . It was reported that Zn²⁺ are colocalized with glutamatergic synaptic vesicles in photoreceptors in the light. We describe that the response of GABAc receptor is reduced by increasing the concentration of Zn²⁺ caused by illumination and the modulatory action of Ca²⁺ and Zn²⁺ on GABAC receptor emphasis of contrast at a dark-light boundary