Aims: Heavy metal cations as Zn2+and Cu2+ moved into the center of scientific interest, because disturbances in the Zn2+ (also in Cu2+) homoeostasis are involved in the pathogenesis of several widespread neurological diseases (1). Zn2+ represents the most important physiological cation of this group. But in basic electrophysiological research Ni2+ cations were routinely used to discriminate between different types of voltage-gated Ca2+ channels (2-4). For the bovine retina, ionotropic GABA receptors participate in the Ni2+-sensitive signalling (5). To test the involvement of Cav2.3 and Cav3.2 in inhibitory retinal signalling during light and dark adaptation, we tested the effect of Ni2+ (15 mM) on murine retinas from controls, Cav2.3-|-, Cav3.2-|-, and double knockout mice. Methods: Isolated murine retinas were mounted in a temperature-controlled recording chamber and perfused with an oxygen-saturated nutrient solution. Electric field potentials were recorded to obtain the full ERG after each flash of light. Results: When Ni2+ (15 mM) is superfused, ERG- responses from the different mouse lines differ from each other, both in magnitudes of amplitudes as well as in the kinetics of the light responses. The murine ERGs are compared to bovine ERGs. Conclusion: These results demonstrate that Ni2+-sensitive voltage-gated Ca2+ channels participate in murine and bovine retinal signalling. Therefore, isolated retinas are useful models to investigate also Zn2+-mediated effects. 1. Zatta, P., et al. and Sensi, S. L. (2009) Trends Pharmacol.Sci. 30, 346-355 2. Zamponi, G. W., Bourinet, E., and Snutch, T. P. (1996) J.Membrane Biol. 151, 77-90 3. Lee, J. H., et al. and Perez-Reyes, E. (1999) Biophys.J. 77, 3034-3042 4. Kang, H. W., et al. and Lee, J. H. (2006) J.Biol.Chem. 281, 4823-4830 5. Siapich, S. A., et al. and Schneider, T. (2009) Acta Ophthalmol. 87, 854-865.