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Fusz K, Kovács-Öller T, Kóbor P, Szabó-Meleg E, Völgyi B, Buzás P, Telkes I. Regional Variation of Gap Junctional Connections in the Mammalian Inner Retina. Cells 2021; 10:2396. [PMID: 34572046 PMCID: PMC8466939 DOI: 10.3390/cells10092396] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/04/2021] [Accepted: 09/07/2021] [Indexed: 11/24/2022] Open
Abstract
The retinas of many species show regional specialisations that are evident in the differences in the processing of visual input from different parts of the visual field. Regional specialisation is thought to reflect an adaptation to the natural visual environment, optical constraints, and lifestyle of the species. Yet, little is known about regional differences in synaptic circuitry. Here, we were interested in the topographical distribution of connexin-36 (Cx36), the major constituent of electrical synapses in the retina. We compared the retinas of mice, rats, and cats to include species with different patterns of regional specialisations in the analysis. First, we used the density of Prox1-immunoreactive amacrine cells as a marker of any regional specialisation, with higher cell density signifying more central regions. Double-labelling experiments showed that Prox1 is expressed in AII amacrine cells in all three species. Interestingly, large Cx36 plaques were attached to about 8-10% of Prox1-positive amacrine cell somata, suggesting the strong electrical coupling of pairs or small clusters of cell bodies. When analysing the regional changes in the volumetric density of Cx36-immunoreactive plaques, we found a tight correlation with the density of Prox1-expressing amacrine cells in the ON, but not in the OFF sublamina in all three species. The results suggest that the relative contribution of electrical synapses to the ON- and OFF-pathways of the retina changes with retinal location, which may contribute to functional ON/OFF asymmetries across the visual field.
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Affiliation(s)
- Katalin Fusz
- Institute of Physiology, Medical School, University of Pécs, 7624 Pécs, Hungary; (K.F.); (P.K.); (I.T.)
- Szentágothai Research Centre, University of Pécs, 7624 Pécs, Hungary; (T.K.-Ö.); (E.S.-M.); (B.V.)
- Centre for Neuroscience, University of Pécs, 7624 Pécs, Hungary
| | - Tamás Kovács-Öller
- Szentágothai Research Centre, University of Pécs, 7624 Pécs, Hungary; (T.K.-Ö.); (E.S.-M.); (B.V.)
- Centre for Neuroscience, University of Pécs, 7624 Pécs, Hungary
- MTA-PTE NAP-2 Retinal Electrical Synapses Research Group, 7624 Pécs, Hungary
| | - Péter Kóbor
- Institute of Physiology, Medical School, University of Pécs, 7624 Pécs, Hungary; (K.F.); (P.K.); (I.T.)
- Szentágothai Research Centre, University of Pécs, 7624 Pécs, Hungary; (T.K.-Ö.); (E.S.-M.); (B.V.)
- Centre for Neuroscience, University of Pécs, 7624 Pécs, Hungary
| | - Edina Szabó-Meleg
- Szentágothai Research Centre, University of Pécs, 7624 Pécs, Hungary; (T.K.-Ö.); (E.S.-M.); (B.V.)
- Institute of Biophysics, Medical School, University of Pécs, 7624 Pécs, Hungary
| | - Béla Völgyi
- Szentágothai Research Centre, University of Pécs, 7624 Pécs, Hungary; (T.K.-Ö.); (E.S.-M.); (B.V.)
- Centre for Neuroscience, University of Pécs, 7624 Pécs, Hungary
- MTA-PTE NAP-2 Retinal Electrical Synapses Research Group, 7624 Pécs, Hungary
- Department of Experimental Zoology and Neurobiology, University of Pécs, 7624 Pécs, Hungary
| | - Péter Buzás
- Institute of Physiology, Medical School, University of Pécs, 7624 Pécs, Hungary; (K.F.); (P.K.); (I.T.)
- Szentágothai Research Centre, University of Pécs, 7624 Pécs, Hungary; (T.K.-Ö.); (E.S.-M.); (B.V.)
- Centre for Neuroscience, University of Pécs, 7624 Pécs, Hungary
| | - Ildikó Telkes
- Institute of Physiology, Medical School, University of Pécs, 7624 Pécs, Hungary; (K.F.); (P.K.); (I.T.)
- Szentágothai Research Centre, University of Pécs, 7624 Pécs, Hungary; (T.K.-Ö.); (E.S.-M.); (B.V.)
- Centre for Neuroscience, University of Pécs, 7624 Pécs, Hungary
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