The development of the labyrinth of the lamprey (
            <i>Lampetra fluviatilis</i>
            Linn. 1758)

Thornhill, R. A.

doi:10.1098/rspb.1972.0045

Cited by 40 publications

(13 citation statements)

References 13 publications

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“…The FITC-phalloidin stain revealed that lamprey hair cells have a substantial infracuticular network of actin penetrating into the hair cell body (Fig. 5B), which may correspond to the striated organelle described by Thornhill (Thornhill, 1972). This is not found in zebrafish hair cells, but a similar network has been described in guinea pig hair cells (Carlisle et al, 1988;…”

Section: Distinct Regions Of the Lamprey Macula Communis Correspond Tmentioning

confidence: 83%

“…1). Adult lamprey inner ears have only two semicircular canals, each with a tricuspid crista, and a single ventrally positioned macula communis that covers the floor of two joined, symmetrical, ciliated chambers (de Burlet and Versteegh, 1930;Lowenstein et al, 1968;Thornhill, 1972;Avallone et al, 2005). A similar pattern, with two semicircular canals, is found in the abundant agnathan fossil record, making it likely that this represents the ancestral condition (Mazan et al, 2000).…”

Section: Introductionmentioning

confidence: 83%

“…Although the lamprey otic vesicle forms by invagination of placodal ectoderm (Thornhill, 1972;Hagelin, 1974), in contrast to the cavitation seen in zebrafish (Haddon and Lewis, 1996), there are parallels between the two species at these early otic vesicle stages. In both species, neuroblasts migrate from ventral regions of the vesicle to form the statoacoustic ganglion anteroventral to the ear, and hair cells develop in two distinct groups at the anterior and posterior of the vesicle (Haddon and Lewis, 1996) (Fig.…”

Section: The Embryonic Lamprey Ear Is Morphologically Asymmetric Aboumentioning

confidence: 94%

“…4); epithelial projections also begin to form the semicircular canal system at this stage. We have not observed any hair cells that obviously correspond to the dorsal macula in the lamprey (Lowenstein et al, 1968;Thornhill, 1972;Hagelin, 1974).…”

Section: The Embryonic Lamprey Ear Is Morphologically Asymmetric Aboumentioning

confidence: 99%

“…Hagfish also have a single macula communis on the ventral floor of the inner ear, but differ in having a single toroidal semicircular canal, which nevertheless is associated with two cristae, and is probably a derived characteristic (Lowenstein and Thornhill, 1970) (for a review, see Lowenstein, 1971). Although the general appearance of the inner ear is symmetrical about the AP axis in adult agnathan fishes, the macula communis can be subdivided into at least three morphologically distinct regions, the anterior horizontal, vertical and posterior horizontal regions (Lowenstein et al, 1968;Lowenstein and Thornhill, 1970;Hagelin, 1974), and there have been several different interpretations of the homology of these regions to the various gnathostome maculae (de Burlet and Versteegh, 1930;Lowenstein et al, 1968;Thornhill, 1972;Hagelin, 1974). Several studies describe hair cell planar polarity patterns in the late larval and adult lamprey and hagfish macula communis as roughly symmetrical about the AP axis (Lowenstein et al, 1968;Lowenstein and Thornhill, 1970;Thornhill, 1972), and Hagelin (Hagelin, 1974) tentatively proposes that both the anterior and posterior ends of the lamprey macula correspond to the gnathostome utricular macula.…”

Section: Introductionmentioning

confidence: 99%

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The developing lamprey ear closely resembles the zebrafish otic vesicle:otx1expression can account for all major patterning differences

Hammond

Whitfield

2006

Development

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The inner ear of adult agnathan vertebrates is relatively symmetric about the anteroposterior axis, with only two semicircular canals and a single sensory macula. This contrasts with the highly asymmetric gnathostome arrangement of three canals and several separate maculae. Symmetric ears can be obtained experimentally in gnathostomes in several ways, including by manipulation of zebrafish Hedgehog signalling, and it has been suggested that these phenotypes might represent an atavistic condition. We have found, however, that the symmetry of the adult lamprey inner ear is not reflected in its early development; the lamprey otic vesicle is highly asymmetric about the anteroposterior axis, both morphologically and molecularly, and bears a striking resemblance to the zebrafish otic vesicle. The single sensory macula originates as two foci of hair cells, and later shows regions of homology to the zebrafish utricular and saccular maculae. It is likely, therefore, that the last common ancestor of lampreys and gnathostomes already had well-defined otic anteroposterior asymmetries. Both lamprey and zebrafish otic vesicles express a target of Hedgehog signalling, patched, indicating that both are responsive to Hedgehog signalling. One significant distinction between agnathans and gnathostomes, however, is the acquisition of otic Otx1 expression in the gnathostome lineage. We show that Otx1 knockdown in zebrafish, as in Otx1 -/-mice, gives rise to lamprey-like inner ears. The role of Otx1 in the gnathostome ear is therefore highly conserved; otic Otx1 expression is likely to account not only for the gain of a third semicircular canal and crista in gnathostomes, but also for the separation of the zones of the single macula into distinct regions.

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Section: Distinct Regions Of the Lamprey Macula Communis Correspond Tmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 83%

Section: The Embryonic Lamprey Ear Is Morphologically Asymmetric Aboumentioning

confidence: 94%

Section: The Embryonic Lamprey Ear Is Morphologically Asymmetric Aboumentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The developing lamprey ear closely resembles the zebrafish otic vesicle:otx1expression can account for all major patterning differences

Hammond

Whitfield

2006

Development

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Standard atlas of the gross anatomy of the developing inner ear of the chicken

1996

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During development, the chicken inner ear undergoes a series of morphological changes which give rise to the various structures found in the adult, including the mature semicircular canals, utricle, saccule, cochlear duct, endolymphatic duct and sac, and neurons of the eighth cranial nerve ganglion. Beginning as a hollow epithelial sphere, the inner ear is sculpted into this complex labyrinth of fluid-filled ducts punctuated by their associated sensory end organs. In this report, the three-dimensional complexity of the developing inner ear of the chicken embryo is documented in the form of a standard atlas. The protocol involved fixation, dehydration, and clearing of embryonic heads harvested at daily intervals, followed by injection of an opaque dye (enamel paint suspension) into the fluid ducts of the inner ear. The position of the ear is shown relative to surface landmarks at seven different stages of development, ranging from embryonic day 5 (E5) to E18. Also shown are higher-power photomicrographs of the inner ear in isolation taken at daily intervals at E3-E17 and viewed from two orthogonal positions. Three orthogonal views are shown at 6-hour intervals during the critical stages of semicircular canal formation (E6-E7). Quantitative measurements of the linear dimensions of the inner ear (dorsoventral, anteroposterior, and mediolateral axes) as a function of time indicate a linear increase in the growth of the ear from E3 through E18. This atlas should prove valuable for evaluating mutant phenotypes in inner ear morphogenesis following gene perturbation experiments in the chicken.

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Hair cell morphological patterns and polarity organization in the sea lamprey vestibular cristae

Fritzsch

Kersigo

Rejent

et al. 2023

The Anatomical Record

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The inner ear of the sea lamprey was examined by scanning electron microscopy, antibody labeling with tubulin, Myo7a, Spectrin, and Phalloidin stain to elucidate the canal cristae organization and the morphology and polarity of the hair cells. We characterized the hair cell stereocilia bundles and their morphological polarity with respect to the kinocilia. We identified three types of hair cells. In Type 1 hair cells, the kinocilia were slightly longer than the tallest stereocilia. This type was located along the medial bank of the crista and their polarity, based on kinocilia location, was uniformly pointed ampullipetally. Type 2 hair cells that had kinocilia that were much longer than the stereocilia, were most abundant in the central region of the crista. This type of hair cell displayed variable polarity. Type 3 hair cells had extremely long kinocilia (~40–50 μm long) and with extremely short stereocilia. They were mostly located in the lateral zone crista and displayed ampullipetal polarity. Myo7a and tubulin antibodies revealed that hair cells and vestibular afferents are distributed across the canal cristae in the lamprey, covering the area of cruciate eminence; a feature that is absent in more derived vertebrates. Spectrin shows hair cells of varying polarities in the central zone. In this zone, some cells followed the main polarity vector (lateral) like those in medial and lateral zones, whereas other cells displayed polarities that carried up to 40° from the main polarity vector.

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The development of the labyrinth of the lamprey ( Lampetra fluviatilis Linn. 1758)

Cited by 40 publications

References 13 publications

The developing lamprey ear closely resembles the zebrafish otic vesicle:otx1expression can account for all major patterning differences

The developing lamprey ear closely resembles the zebrafish otic vesicle:otx1expression can account for all major patterning differences

Standard atlas of the gross anatomy of the developing inner ear of the chicken

Hair cell morphological patterns and polarity organization in the sea lamprey vestibular cristae

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