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In Vivo Spontaneous Calcium Activity Imaging of Zebrafish Hair Cells

Wednesday, September 12, 2018 — Poster Session I

12:00 p.m. – 1:30 p.m.
FAES Terrace
NIDCD
DEVBIO-5

Authors

  • OA Hamdi
  • Q Zhang
  • A Beirl
  • K Kindt

Abstract

Spontaneous activity (SA) is an intrinsically generated neuronal activity that occurs in the absence of external stimuli. SA is present in sensory systems such as the developing mammalian inner ear. This SA is thought to be important to help establish neuronal connections and shape and maintain the organization of the auditory pathway. The boney structure of the mammalian ear makes it challenging to access the specialized in vivo environment required to study hair‐cell SA. Zebrafish is a unique and advantageous animal model for studying the SA of hair cells in vivo where both hair cells of the inner ear and lateral line system can easily be accessed. We use genetically encoded calcium indicators combined with swept field confocal microscopy to image and demonstrate the presence of SA in zebrafish hair cells. A MATLAB program was developed to analyze and quantify our SA raw imaging data; employing a selective criterion for peak identification. To understand what factors are required to generate SA, we used both pharmacological and genetic approaches to alter either the mechanosensitive or synaptic function intrinsic to hair cells. We found genetic ablation of the presynaptic calcium channel, CaV1.3 abolishes all SA, which suggests that calcium SA originates from the calcium influx from Cav1.3 channel in the hair cells. Pharmacological or genetic ablation of mechanosensitive function reduced SA, indicating mechanotransduction may play an important role in regulating SA. Overall, understanding how SA is generated in hair cells will help us understand its specific role in synapse formation and maintenance.

Category: Developmental Biology