Presynaptic CaV1.3 Channels Regulate Synaptic Ribbon Size and Are Required for Synaptic Maintenance in Sensory Hair Cells
- Authors
- Sheets, L., Kindt, K.S., and Nicolson, T.
- ID
- ZDB-PUB-121206-19
- Date
- 2012
- Source
- The Journal of neuroscience : the official journal of the Society for Neuroscience 32(48): 17273-17286 (Journal)
- Registered Authors
- Kindt, Katie, Nicolson, Teresa, Sheets, Lavinia
- Keywords
- none
- MeSH Terms
-
- Animals
- Calcium Channels, L-Type/genetics
- Calcium Channels, L-Type/metabolism*
- Hair Cells, Auditory/cytology
- Hair Cells, Auditory/metabolism*
- Synapses/genetics
- Synapses/metabolism*
- Synaptic Transmission/physiology*
- Synaptic Vesicles/genetics
- Synaptic Vesicles/metabolism
- Zebrafish/metabolism*
- PubMed
- 23197719 Full text @ J. Neurosci.
L-type calcium channels (CaV1) are involved in diverse processes, such as neurotransmission, hormone secretion, muscle contraction, and gene expression. In this study, we uncover a role for CaV1.3a in regulating the architecture of a cellular structure, the ribbon synapse, in developing zebrafish sensory hair cells. By combining in vivo calcium imaging with confocal and super-resolution structured illumination microscopy, we found that genetic disruption or acute block of CaV1.3a channels led to enlargement of synaptic ribbons in hair cells. Conversely, activating channels reduced both synaptic-ribbon size and the number of intact synapses. Along with enlarged presynaptic ribbons in caV1.3a mutants, we observed a profound loss of juxtaposition between presynaptic and postsynaptic components. These synaptic defects are not attributable to loss of neurotransmission, because vglut3 mutants lacking neurotransmitter release develop relatively normal hair-cell synapses. Moreover, regulation of synaptic-ribbon size by Ca2+ influx may be used by other cell types, because we observed similar pharmacological effects on pinealocyte synaptic ribbons. Our results indicate that Ca2+ influx through CaV1.3 fine tunes synaptic ribbon size during hair-cell maturation and that CaV1.3 is required for synaptic maintenance.