Prenatal maturation of endocochlear potential and electrolyte composition of inner ear fluids in guinea pigs

Raphael, Yehoash; Ohmura, Masaki; Kanoh, Naoyuki; Yagi, Nobuya; Makimoto, Kazuo

doi:10.1007/bf00463614

Cited by 19 publications

(11 citation statements)

References 8 publications

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“…The guinea pigs showed abundant expression of ZO-1 both at the apical surfaces of the marginal cells and in the basal cell layer from PND 1 (Figures 6E and 6F). Morphometric data confirmed that on PND 1, the Cx26-positive area per area of spiral ligament reached the adult level in guinea pigs (no significant difference between PND 1 and PND 70) ( Figure 6I), which coincided with the endocochlear potential of neonatal and adult guinea pigs reported by Raphael et al (1983). Morphometric analysis for ZO-1 expression in the basal cell layer of the cochlea showed no significant difference between neonatal and adult guinea pigs of PND 70 ( Figure 6J).…”

Section: Cx26 and Zo-1 In The Cochlea Of Neonatal And Adult Guinea Pigssupporting

confidence: 78%

Different Regulation of Connexin26 and ZO-1 in Cochleas of Developing Rats and of Guinea Pigs with Endolymphatic Hydrops

Suzuki

Oyamada

Takamatsu

2001

J Histochem Cytochem.

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Using confocal microscopy and morphometry, we analyzed the expression of connexin26 (Cx26) and ZO-1 in rat cochlea during the postnatal period to elucidate spatiotemporal changes in gap junctions and tight junctions during auditory development. We also studied changes in these junctions in experimental endolymphatic hydrops in the guinea pig. In the adult rat cochlear lateral wall, Cx26 was detected in fibrocytes in the spiral ligament and in the basal cell layer of the stria vascularis, whereas ZO-1 was detected in the apical surfaces of marginal cells and in the basal cell layer. During postnatal development, Cx26 expression increased mainly in the spiral ligament, whereas ZO-1 expression increased in the basal cell layer. The morphometry of Cx26 showed a sigmoid time course with a rapid increase on postnatal day (PND) 14, whereas that of ZO-1 showed a marked increase on PND 7. In experimental endolymphatic hydrops, the expression of Cx26 significantly decreased, whereas there were no obvious changes in the expression of ZO-1. These results indicate that gap junctions and tight junctions in the cochlea increase in a different spatiotemporal manner during the development of auditory function and that gap junctions and tight junctions in the cochlea are differentially regulated in experimental endolymphatic hydrops. (J Histochem Cytochem 49:573-586, 2001)

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Section: Cx26 and Zo-1 In The Cochlea Of Neonatal And Adult Guinea Pigssupporting

confidence: 78%

Different Regulation of Connexin26 and ZO-1 in Cochleas of Developing Rats and of Guinea Pigs with Endolymphatic Hydrops

Suzuki

Oyamada

Takamatsu

2001

J Histochem Cytochem.

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“…The morphological maturation of the fine structure of the stria vascularis of the guinea pig has been correlated with the subsequent onset of a positive endocochlear potential (EP) from E62 and a rapid elevation to the adult level at birth (Raphael et al 1983). In mice and rats, the EP increases between 8 and 13 days after birth and reaches its adult-like level at 16-17 days after birth (Rübsamen and Lippe 1998).…”

Section: Few Mesenchymal Cells Within the Spiral Ligament (Including mentioning

confidence: 99%

Malformation of stria vascularis in the developing inner ear of the German waltzing guinea pig

et al. 2007

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Auditory function and cochlear morphology have previously been described in the postnatal German waltzing guinea pig, a strain with recessive deafness. In the present study, cochlear histopathology was further investigated in the inner ear of the developing German waltzing guinea pig (gw/gw). The lumen of the cochlear duct diminished progressively from embryonic day (E) 35 to E45 and was absent at E50 because of the complete collapse of Reissner's membrane onto the hearing organ. The embryonic stria vascularis, consisting of a simple epithelium, failed to transform into the complex trilaminar tissue seen in normal animals and displayed signs of degeneration. Subsequent degeneration of the sensory epithelium was observed from E50 and onwards. Defective and insufficient numbers of melanocytes were observed in the developing gw/gw stria vascularis. A gene involved in cochlear melanocyte development, Pax3, was markedly reduced in lateral wall tissue of the cochlea of both E40 and adult gw/gw individuals, whereas its expression was normal in the skin and diaphragm muscle of adult gw/gw animals. The Pax3 gene may thus be involved in the pathological process but is unlikely to be the primary mutated gene in the German waltzing guinea pig. TUNEL assay showed no signs of apoptotic cell death in the developing stria vascularis of this type of guinea pig. Thus, malformation of the stria vascularis appears to be the primary defect in the inner ear of the German waltzing guinea pig. Defective and insufficient numbers of melanocytes might migrate to the developing stria vascularis but fail to provide the proper support for the subsequent development of marginal and basal cells, thereby leading to stria vascularis malformation and dysfunction in the inner ear of the German waltzing guinea pig.

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“…A good candidate for this model is the guinea pig since, similar to human neonates, they begin to hear in utero [Raphael et al, 1983] and guinea pigs have been used to access some aspects of postnatal auditory development [Dum, 1984;Walger et al, 1993]. The purpose of the present study was therefore to use clinical tests of auditory function in guinea pigs in order to document, under controlled conditions, the function of several parts of the auditory pathway -external ear, tympanic membrane (TM), ME, hair cells, auditory nerve and brainstem auditory pathway -longitudinally and comprehensively, until they reach adult-like values and to try to gain insight into the possible mechanisms of these changes.…”

Section: Introductionmentioning

confidence: 99%

The Neonate Has a Temporary Conductive Hearing Loss due to Fluid in the Middle Ear

Priner

Freeman²,

Perez³

et al. 2003

Audiol Neurotol

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Postnatal functional changes in the activity of the ear and auditory pathway in neonatal guinea pigs [from day of birth (postnatal day, PND = 0), PNDs 1–4, 7 and then weekly up to 7 weeks] were studied as a model of maturation of hearing in human neonates. On the day of birth there were signs of a conductive hearing loss: negative middle ear pressure, auditory nerve brainstem evoked response (ABR) threshold elevation, ABR wave 1 latency prolongation and low amplitude otoacoustic emissions. The conductive hearing loss is probably a result of the (amniotic) fluid found in the neonatal middle-ear cavity. Over the next PNDs, this conductive hearing loss was resolved. In order to confirm this neonatal conductive hearing loss and its resolution, saline was instilled into the middle ear of guinea pigs. This induced signs of a conductive hearing loss similar to those seen in the neonatal guinea pigs which disappeared with clearance of this fluid. Therefore it may be concluded that most of the changes in auditory function seen over the first PNDs are due to absorption of amniotic fluid from the middle-ear cavity.

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Prenatal maturation of endocochlear potential and electrolyte composition of inner ear fluids in guinea pigs

Cited by 19 publications

References 8 publications

Different Regulation of Connexin26 and ZO-1 in Cochleas of Developing Rats and of Guinea Pigs with Endolymphatic Hydrops

Different Regulation of Connexin26 and ZO-1 in Cochleas of Developing Rats and of Guinea Pigs with Endolymphatic Hydrops

Malformation of stria vascularis in the developing inner ear of the German waltzing guinea pig

The Neonate Has a Temporary Conductive Hearing Loss due to Fluid in the Middle Ear

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