Development
Author: Matias Rodriguez | Email: matti.rodriguez@hotmail.com
Matias Rodriguez1°, Lucia Salatino1°,Ana Belen Elgoyhen2°, Paola V. Plazas1°
1° Instituto de Farmacología, Facultad de Medicina
2° INGEBI, CONICET
Spontaneous electrical activity (SEA) is required for the proper establishment of sensory systems. We use Zebrafish (Danio rerio) lateral line (LL) to decipher the mechanisms by which SEA affects the assembly of developing sensory circuits. The LL allows fishes and amphibians to detect water motion and pressure changes and consists of clusters of neuromasts, which contains mechanosensory hair cells (HC) innervated by afferent (Aff) and efferent neurons.. We over-expressed hKir2.1 channels to silence SEA in single LL Aff and examined axonal arbor growth in competitive (active neighboring axons) and non-competitive (global suppression of SEA, inactive neighboring axons) environments. Our results indicate that silencing single LL Aff in a competitive environment, reduced innervation area, altered axonal arbor complexity, and increased branch formation, elimination, retraction and elongation rates. In contrast, global suppression of SEA, did not affect innervation area but led to unstable axonal arbors, with increased branch retraction and elongation rates. These results suggest that SEA regulates branch elongation and retraction regardless of activity in neighboring cells, but the ability to arrest branch formation and elimination, and to regulate arbor territory, is an activity-dependent competitive process. Our study provides in vivo evidence that an activity-based competition rule regulates axonal arbor growth and maturation of developing LL Aff.