Organization of the lateral line system in embryonic zebrafish

Abstract

We describe the organization of lateral line nerves and ganglia in the embryonic zebrafish, Danio rerio. Two lateral line nerves are found anterior to the otic vesicle: the anterodorsal nerve innervates neuromasts of the supraorbital, infraorbital, and otic lines, whereas the anteroventral nerve innervates the mandibular and opercular lines. An additional two lateral line nerves are found posterior to the otic vesicle: the middle lateral line nerve innervates the middle line, whereas the posterior nerve innervates the occipital dorsal and posterior trunk lines. Preotic nerves converge on a single entry zone into the central nervous system at the facial motor root (mVII), as do axons of the octaval nerve. Postotic nerves converge to a posterior entry zone at the glossopharyngeal root. Both lateral line ganglia and neuromasts develop on a stereotypical schedule. To examine the segmental relationships among cranial ganglia, neural crest, and hindbrain, lateral line organization was analyzed in valentino mutants, which have disruptions in the development of rhombomeres 5–7 and in the third arch neural crest, and are missing glossopharyngeal motor neurons. The proposed corresponding lateral line nerve for this head segment, the middle lateral line, appears to develop normally. However, the middle and posterior nerves do not form a posterior entry zone in the absence of a glossopharyngeal root in val mutants, but instead course anteriorly to join the preotic nerves. J. Comp. Neurol. 421:189–198, 2000. © 2000 Wiley‐Liss, Inc.

Development of the zebrafish inner ear

“…SAg neurons will send projections back to the ear's sensory patches. Neuroanatomy of the VIIIth nerve has been briefly described with antibody staining for later stages (Raible and Kruse, 2000).…”

Visualization of two distinct classes of neurons by gad2 and zic1 promoter/enhancer elements in the dorsal hindbrain of developing zebrafish reveals neuronal connectivity related to the auditory and lateral line systems

“…The sensory receptors in these systems are hair cells. Each type of sensory information enters adjacent but nonoverlapping regions of the dorsal hindbrain by means of the eighth nerve or the lateral line nerves (Piotrowski and Northcutt, 1996;Raible and Kruse, 2000). Various classes of interneurons have been described in this complex but phylogenetically conserved structure, based on their morphologies, connectivity, and physiological properties in adult animals from fish to mammals (Knudsen, 1977;McCormick, 1989;New et al, 1996;Cant and Benson, 2003).…”

Cadherin‐4 plays a role in the development of zebrafish cranial ganglia and lateral line system

“…The zebrafish cranial ganglia, located ventrolateral to the hindbrain, consist of the trigeminal (gV), facial (gVII), statoacoustic (gVIII), glossopharyngeal (gIX), and vagal (gX) ganglia (Raible and Kruse, 2000). The gV becomes recognizable as early as 9 hr post fertilization (hpf), the earliest of the cranial ganglia (Andermann et al, 2002).…”

“…The remaining cranial ganglia (gVII and gX) are formed later (after 36 hpf). The zebrafish lateral line system contains four ganglia and sets of neuromasts (Metcalfe, 1985(Metcalfe, , 1989Raible and Kruse, 2000). The posterior lateral line ganglion (gP), caudal to the otic vesicle, can be recognized as early as 14 hpf (Andermann et al, 2002).…”

“…The anterodorsal ganglion (gAD) and anteroventral ganglion (gAV), located anterior to the otic vesicle, develop from the anterior lateral line placode area around 24 hpf, while the middle lateral line ganglion (gM), located anteromedial to the gP, develops after 26 hpf (Andermann et al, 2002). The gAD and gAV partially fuse with gV and the gVII, respectively, during development (Higashijima et al, 2000;Raible and Kruse, 2000). The neuromasts on the head, jaw, and opercle originate from the anterior lateral line (ALL) primordium, while the neuromasts caudal to the otic vesicle develop from the posterior lateral line primordium (PLLp) (Metcalfe, 1985(Metcalfe, , 1989Raible and Kruse, 2000).…”