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Sensory Epithelia (sensory + epithelia)
Selected AbstractsDiverse expression patterns of LIM-homeodomain transcription factors (LIM-HDs) in mammalian inner ear developmentDEVELOPMENTAL DYNAMICS, Issue 11 2008Mingqian Huang Abstract LIM-homeodomain transcription factors (LIM-HDs) are essential in tissue patterning and differentiation. But their expression patterns in the inner ear are largely unknown. Here we report on a study of twelve LIM-HDs, by their tempo-spatial patterns that imply distinct yet overlapping roles, in the developing mouse inner ear. Expression of Lmx1a and Isl1 begins in the otocyst stage, with Lmx1a exclusively in the non-sensory and Isl1 in the prosensory epithelia. The second wave of expression at E12.5 includes Lhx3, 5, 9, Isl2, and Lmx1b in the differentiating sensory epithelia with cellular specificities. With the exception of Lmx1a and Lhx3, all LIM-HDs are expressed in ganglion neurons. Expression of multiple LIM-HDs within a cell type suggests their redundant function. Developmental Dynamics 237:3305,3312, 2008. © 2008 Wiley-Liss, Inc. [source] Comparative analysis of Gata3 and Gata2 expression during chicken inner ear developmentDEVELOPMENTAL DYNAMICS, Issue 1 2007Kersti Lilleväli Abstract The inner ear is a complex sensory organ with hearing and balance functions. Gata3 and Gata2 are expressed in the inner ear, and to gain more insight into their roles in otic development, we made a detailed expression analysis in chicken embryos. At early stages, their expression was highly overlapping. At later stages, Gata2 expression became prominent in vestibular and cochlear nonsensory epithelia. In contrast to Gata2, Gata3 was mainly expressed in the developing sensory epithelia, reflecting the importance of this factor in the sensory,neural development of the inner ear. While the later expression patterns of both Gata3 and Gata2 were highly conserved between chicken and mouse, important differences were observed especially with Gata3 during early otic development, providing indications of divergent molecular control during placode invagination in mice and chickens. We also found indications that the regulatory hierarchy observed in mouse, where Gata3 is upstream of Gata2 and Fgf10, could be conserved in chicken. Developmental Dynamics 236:306,313, 2007. © 2006 Wiley-Liss, Inc. [source] Differential expression of Na,K-ATPase , and , subunit genes in the developing zebrafish inner earDEVELOPMENTAL DYNAMICS, Issue 3 2003Brian Blasiole Abstract We have used whole-mount in situ hybridization to analyze Na,K-ATPase , and , subunit gene expression in the developing zebrafish ear. Four ,1-like (,1a.1, ,1a.2, ,1a.4, and ,1a.5) and two , (,1a and ,2b) subunit genes are expressed in ear beginning at mid-somitogenesis. Each gene exhibits a distinct spatial and temporal expression pattern. The ,1a.1 gene was ubiquitously expressed in the otic epithelium from mid-somitogenesis to 24 hr postfertilization (hpf). Expression of this gene was gradually reduced and by 48 hpf, ,1a.1 transcripts were no longer detectable in the ear. The ,1a.2 and ,1a.5 genes were expressed in regions that correspond to the anterior macula, lateral crista, and semicircular canal projections up to 48 hpf. At later stages, expression of these genes was limited to cells in the dorsolateral septum and semicircular canal projections. ,1a.4 and ,1a transcripts were ubiquitously expressed during ear development and were present in most otic tissues at 5 days postfertilization (dpf). Expression of the ,2b gene, on the other hand, was restricted to subsets of cells that form sensory epithelia. These results strongly suggest different functional roles for individual Na,K-ATPase genes in zebrafish ear development. Na,K-ATPase genes are likely to represent useful markers for the analysis of zebrafish otogenesis. Development Dynamics, 2003. © 2003 Wiley-Liss, Inc. [source] Clinical application of neurotrophic factors: the potential for primary auditory neuron protectionEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2005Lisa N. Gillespie Abstract Sensorineural hearing loss, as a result of damage to or destruction of the sensory epithelia within the cochlea, is a common cause of deafness. The subsequent degeneration of the neural elements within the inner ear may impinge upon the efficacy of the cochlear implant. Experimental studies have demonstrated that neurotrophic factors can prevent this degeneration in animal models of deafness, and can even provide functional benefits. Neurotrophic factor therapy may therefore provide similar protective effects in humans, resulting in improved speech perception outcomes among cochlear implant patients. There are, however, numerous issues pertaining to delivery techniques and treatment regimes that need to be addressed prior to any clinical application. This review considers these issues in view of the potential therapeutic application of neurotrophic factors within the auditory system. [source] ,-Aminobutyric acid is present in a spatially discrete subpopulation of hair cells in the crista ampullaris of the toadfish Opsanus tauTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 1 2004Gay R. Holstein Abstract Although ,-aminobutyric acid (GABA) and glutamate are known to be present in the vestibular sensory epithelia of a variety of species, the functional relationship between these two transmitters is not clear. The present study addresses the three-dimensional spatial distribution of GABA and glutamate immunoreactivity in the vestibular labyrinth of the oyster toadfish by using whole end organs labeled by immunofluorescence with monoclonal anti-GABA and/or antiglutamate antibodies and visualized as whole mounts by multiphoton confocal microscopy. We find glutamate-immunoreactive hair cells present throughout the sensory epithelium. In contrast, prominent GABA immunoreactivity is restricted to a small population of hair cells located in the central region of the crista. Double immunofluorescence reveals two distinct staining patterns in GABA-labeled hair cells. Most (,80%) GABA-labeled cells show trace levels of glutamate, appropriate for the metabolic/synthetic role of cytoplasmic glutamate. The remainder of the GABA-stained cells contain substantial levels of both GABA and glutamate, suggesting transmitter colocalization. In the toadfish utricle, glutamatergic hair cells are present throughout the macula. GABA-immunoreactive hair cells follow the arc of the striola, and most GABA-labeled receptor cells coexpress glutamate. The localization of GABA was explored in other species as well. In the pigeon, GABAergic hair cells are present throughout the crista ampullaris. Our findings demonstrate that multiple, neurochemically distinct types of hair cells are present in vestibular sensory epithelia. These observations, together with the excitatory activity generally associated with 8th nerve afferent fibers, strongly suggest that GABA serves an important, specific, and complex role in determining primary afferent response dynamics. J. Comp. Neurol. 471:1,10, 2004. © 2004 Wiley-Liss, Inc. [source] | ||||||||||