CHARACTERIZATION OF SPONTANEOUS ELECTRICAL ACTIVITY IN DEVELOPING ZEBRAFISH LATERAL LINE HAIR CELLS

LUCIA SALATINO; A.B. ELGOYHEN; JUAN GOUTMAN; PAOLA PLAZAS

Congreso; XXXVII Congreso Anual de la Sociedad Argentina de Investigaciones en Neurociencias; 2022

Spontaneous electrical activity (SEA) transmitted among developing neurons shapes the connectivity patterns of emerging circuits. In the mammalian inner ear, SEA is originated in the cochlea by the release of glutamate from sensory hair cells (HC). In order to study SEA in developing HC, we used the Zebrafish (Danio rerio) lateral line system (zLL). The zLL allows fishes and amphibians to detect water motion and pressure changes and consists of clusters of mechanosensitive HC. LL HC are innervated by afferent and efferent neurons, and share structural, molecular and functional properties with those of the cochlea. zLL forms at 2-3 days post-fertilization (dpf) and the system is completely mature at 5 dpf. Previous work has shown that zLL HC exhibits SEA at 3 and 6 dpf. In this work, we have taken advantage of the optical transparency and rapid development of zebrafish to study the patterns of SEA in developing LL HC. We performed in vivo calcium imaging in transgenic larvae expressing GCaMP7 in zLL HC and found that HC display two types of spontaneous calcium transients, waves and spikes, from 3 to 7 dpf. The magnitude of SEA changes over this temporal window. Moreover, specific patterns of calcium activity are present at different developmental stages, suggesting its relation to the establishment of zLL microcircuit.