December 2002
Volume 43, Issue 13
ARVO Annual Meeting Abstract  |   December 2002
Photoreceptor Voltage Dependent Calcium Channels but not Bipolar Cell Activity is Required for Normal Ribbon Synapse Formation
Author Affiliations & Notes
  • RG Gregg
    University of Louisville Louisville KY
    Biochemistry & Molecular Biology and Ophthal & Vis Sci
  • DS Read
    Biochemistry & Molecular Biology
    University of Louisville Louisville KY
  • NS Peachey
    Cole Eye Institute Cleveland Clinic Foundation & Cleveland VAMC Cleveland OH
  • MT Pardue
    Ophthalmology Atlanta VAMC & Emory University Atlanta GA
  • MA McCall
    Psychological & Brain Sciences and Ophthal & Vis Sci
    University of Louisville Louisville KY
  • Footnotes
    Commercial Relationships   R.G. Gregg, None; D.S. Read, None; N.S. Peachey, None; M.T. Pardue, None; M.A. McCall, None. Grant Identification: Support: NIH EY12354
Investigative Ophthalmology & Visual Science December 2002, Vol.43, 831. doi:
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    • Get Citation

      RG Gregg, DS Read, NS Peachey, MT Pardue, MA McCall; Photoreceptor Voltage Dependent Calcium Channels but not Bipolar Cell Activity is Required for Normal Ribbon Synapse Formation . Invest. Ophthalmol. Vis. Sci. 2002;43(13):831.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract: : Purpose: Transmission between photoreceptors and bipolar cells is mediated by release of neurotransmitter at the ribbon synapse. We have identified two mouse lines, nob (Pardue et al., IOVS. 39:2443) and CNS-ß2 null that lack a bipolar cell response as determined by absence of the ERG b-wave. The thickness of the OPL in the nob mouse is normal, whereas the OPL in CNS-ß2 null mice is considerably thinner. To examine the mechanism of this defect, synapse morphology and the expression pattern of synaptic proteins was examined during development. Methods: OPL synapse morphology was examined in both lines of mice and compared to control littermates using electron microscopy and immunohistochemistry of synapse specific proteins: synaptophysin, bassoon and B16. Results: The ribbon synapses in the OPL of nob mice appear normal. In contrast, the CNS-ß2 null mice have an almost complete loss of the ribbon synapses. Analyses of CNS-ß2 null and control mice at 7 days of age indicate that ribbons synapses form in similar numbers. Immunohistochemical analyses of bassoon expression at 7 days of age shows a horseshoe shaped staining pattern in controls. In the CNS-ß2 null mice, there is a punctate staining pattern and there is a greatly reduced number of horseshoe shaped structures. Conclusion: These data indicate that the invagination of the bipoar cells into the terminal of the photoreceptor may not occur in the CNS-ß2 null mice. The fact that these mouse models lack ERG b-waves but only the CNS-ß2 null shows abnormalities in OPL synaptic architecture indicates bipolar cell function is not required for ribbon synapse formation. In contrast, the presence of the photoreceptor voltage dependent calcium channel is required normal formation of the ribbon synapse.

Keywords: 564 retinal development • 445 ion channels • 594 synapse 

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