034 | Resolving intracellular signalling behind Müller glial intrinsic photosensitivity

Cellular and Molecular Neurobiology

Author: NATALIA ANDREA MARCHESE | Email: natalia.marchese@unc.edu.ar

Natalia Andrea Marchese , Maximiliano Nicolás Rios , Agustín Yaneff , Carlos Davio , Mario Eduardo Guido

2° ININFA (UBA-CONICET)- Catedra de Quimica Medicinal (FFyB–UBA)

The retina captures light for image and non-image forming functions through two sets of specialized photoreceptors cells. Remarkably, Müller glia (MC), derived from neuronal precursors and the most abundant retinal glial cell type, have been shown to express blue- and UV-sensitive opsins (Opn3, RGR and Opn5) and to respond to blue light (BL) via G-protein signaling towards calcium release from internal stores. We aimed to further characterize the intrinsic photoreceptor capacity of the inner retina focusing on MC.
MC primary cultures obtained from chicken embryos (E8) stimulated with BL (480 nm), were monitored for cAMP cellular responses by RIA and fixed for ICC detection of transcriptional factors activated by BL.
We present our recent results showing intrinsic cellular responses in primary cultures of avian MC elicited by BL. MC in culture displayed marked increases in their intracellular cAMP levels 5-10 min after BL stimulation (1min), which returned to basal levels 30 min after stimulation. This response showed dependence on opsin activation concomitant with p-CREB nuclear translocation beginning 30 min after BL stimulus.
Overall, our results indicate mixed intracellular responses in MC in culture induced by BL, implying both calcium and cAMP signaling. The complex output in MC intrinsic photosensitivity, remains to be elucidated; considering their multiple described functions our results suggest a higher level of complexity for light detection within the retina.