Anatomy of the posterior lateral line system in young larvae of the zebrafish

Abstract

We studied the anatomy of neuromasts, afferent sensory neurons, and efferent neurons of the midbody branch of the posterior lateral line in larvae of the zebrafish (Brachydanio rerio), 5 days after fertilization. This simple sensory system consists of ten or 11 neuromasts, 15-20 sensory neurons, and about nine efferent neurons. The neuromasts are typical free neuromasts and both afferent and efferent synapses are present on hair cells within them. The sensory neurons project into a single longitudinal column of neuropil in the hindbrain. The sensory terminals appear by light microscopy to contact the dorsolateral dendrite of the ipsilateral Mauthner cell. Three types of efferent neurons are present; two types in the hindbrain and one type in the diencephalon. We provide several lines of evidence that demonstrate that these central neurons are efferent to the lateral line. We conclude from this morphology that the larval system includes all of the components of the adult system and is probably functional at this early stage. We also found that larvae have all of the efferent neurons found in adult zebrafish, while the number of neuromasts and sensory neurons will increase during subsequent development.

Bax, Bcl2, and p53 Differentially Regulate Neomycin- and Gentamicin-Induced Hair Cell Death in the Zebrafish Lateral Line

“…A neuromast with intense labeling was scored "2," one with dim labeling was scored "1," and one with no labeling was scored "0," yielding a score of 0-20 for each fish. We assessed the same 10 neuromasts for each fish, which have highly stereotyped positioning in 5-6 dpf zebrafish (Metcalf et al 1985;Raible and Kruse 2000). DASPEI assessment was performed for 7-14 fish per treatment combination.…”

“…Lateral line hair cells cluster in sensory organs called neuromasts that are externally located on the head and body of the animal (Metcalf et al 1985;Coombs et al 1989;Raible and Kruse 2000). This sensory system is used to detect nearfield water movement and mediates a number of important behaviors including predator avoidance, prey capture, and orientation to flow (Dijkgraaf 1963;Montgomery and MacDonald 1987;Montgomery et al 1997;Coombs et al 2001;New et al 2001;Suli et al 2012).…”

Cloning and expression of three zebrafish roundabout homologs suggest roles in axon guidance and cell migration

“…The PLL is a sensory system that detects water flow via hair cells in the neuromasts. The neuromasts are positioned in a line along the body and arise from a migrating cell mass called the PLL primordium (Metcalfe, 1985;Metcalfe et al, 1985). At 24hpf, robo1 expression is found in the primordium at the level of the 5th somite (Figs.…”

Molecular cloning and embryonic expression of zebrafish PCSK5 co‐orthologues: Functional assessment during lateral line development

“…The migration of the posterior lateral line primordium gives rise to the development of the posterior lateral line with the neuromasts on the trunk and tail. Towards the end of zebrafish embryogenesis, the lateral line comprises 7-8 neuromasts regularly spaced between the ear and the tip of the tail (Metcalfe, 1985(Metcalfe, , 1989Metcalfe et al, 1985;Gompel et al, 2001;Itoh and Chitnis, 2001;Dambly-Chaudiere et al, 2003;Ghysen and Dambly-Chaudiere, 2004). The heterogeneous labelling of the primordium by the CB701 and CB403 markers revealed that the primordium is dynamically pre-patterned, and that clusters of cells corresponding to presumptive neuromasts are already defined within the primordium several hours before their deposition (Gompel et al, 2001).…”