ZFIN ID: ZDB-PUB-121206-19
Presynaptic CaV1.3 Channels Regulate Synaptic Ribbon Size and Are Required for Synaptic Maintenance in Sensory Hair Cells
Sheets, L., Kindt, K.S., and Nicolson, T.
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.