| First Author | Lüke JN | Year | 2020 |
| Journal | BMC Ophthalmol | Volume | 20 |
| Issue | 1 | Pages | 182 |
| PubMed ID | 32375703 | Mgi Jnum | J:337340 |
| Mgi Id | MGI:6728599 | Doi | 10.1186/s12886-020-01451-8 |
| Citation | Luke JN, et al. (2020) Submicromolar copper (II) ions stimulate transretinal signaling in the isolated retina from wild type but not from Cav2.3-deficient mice. BMC Ophthalmol 20(1):182 |
| abstractText | BACKGROUND: So far, only indirect evidence exists for the pharmacoresistant R-type voltage-gated Ca(2+) channel (VGCC) to be involved in transretinal signaling by triggering GABA-release onto ON-bipolar neurons. This release of inhibitory neurotransmitters was deduced from the sensitivity of the b-wave to stimulation by Ni(2+), Zn(2+) and Cu(2+). To further confirm the interpretation of these findings, we compared the effects of Cu(2+) application and chelation (using kainic acid, KA) on the neural retina from wildtype and Cav2.3-deficient mice. Furthermore, the immediately effect of KA on the ERG b-wave modulation was assessed. METHODS: Transretinal signaling was recorded as an ERG from the superfused murine retina isolated from wildtype and Cav2.3-deficient mice. RESULTS: In mice, the stimulating effect of 100 nM CuCl2 is absent in the retinae from Cav2.3-deficient mice, but prominent in Cav2.3-competent mice. Application of up to 3 mM tricine does not affect the murine b-wave in both genotypes, most likely because of chelating amino acids present in the murine nutrient solution. Application of 27 muM KA significantly increased the b-wave amplitude in wild type and Cav2.3 (-|-) mice. This effect can most likely be explained by the stimulation of endogenous KA-receptors described in horizontal, OFF-bipolar, amacrine or ganglion cells, which could not be fully blocked in the present study. CONCLUSION: Cu(2+)-dependent modulation of transretinal signaling only occurs in the murine retina from Cav2.3 competent mice, supporting the ideas derived from previous work in the bovine retina that R-type Ca(2+) channels are involved in shaping transretinal responses during light perception. |
