Age‐related changes in the olfactory system of dogs

Hirai, Toshikazu; Kojima, Seiji; Shimada, Akinori; Umemura, Takashi; Sakai, Masao; Itakura, Chitoshi

doi:10.1111/j.1365-2990.1996.tb01132.x

Cited by 53 publications

(38 citation statements)

References 25 publications

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“…Aging studies have shown a decrease in both the number and the length of epithelial microvilli and a declined function of plasma membrane enzymes and receptors (32)(33)(34)(35). Specifically, the decrease in the activity of some of the enzymes …”

Section: Discussionmentioning

confidence: 99%

Proteomic Characterization of Isolated Retinal Pigment Epithelium Microvilli

Bonilha

Bhattacharya

West

et al. 2004

Molecular & Cellular Proteomics

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Polarized epithelial cells are characterized by displaying compartmentalized functions associated with differential distribution of transporters, structural proteins, and signaling molecules on their apical and basolateral surfaces. Their apical surfaces frequently elaborate microvilli, which vary in structure according to the specific type and function of each epithelium. The molecular basis of this heterogeneity is poorly understood. However, differences in function will undoubtedly be reflected in the specific molecular composition of the apical surface in each epithelial subtype. We have exploited a method for isolating microvilli from the mouse eye using wheat germ agglutinin (WGA)-agarose beads to begin to understand the specific molecular composition of apical microvilli of the retinal pigment epithelium (RPE) and expand our knowledge of the potential function of this interface. Initially, apical RPE plasma membranes bound to WGA beads were processed for morphological analysis using known apical and basolateral surface markers. The protein composition of the apical microvilli was then established using proteomic analysis. Over 200 proteins were identified, including a number of proteins previously known to be localized to RPE microvilli, as well as others not known to be present at this surface. Localization of novel proteins identified with proteomics was confirmed by immunohistochemistry in both mouse and rat eye tissue. The data generated provides new information on the protein composition of the RPE apical microvilli. The isolation technique used should be amenable for isolating microvilli in other epithelia as well, allowing new insights into additional functions of this important epithelial compartment. Molecular & Cellular Proteomics 3:1119 -1127, 2004.Epithelial cells are characterized by the asymmetric distribution of proteins and lipids in their plasma membrane: a basic feature referred to as polarity. The functional polarity of epithelial cells is dependent on the asymmetric distribution of specific enzymes, signaling molecules, and transport proteins between their apical and basolateral surface membranes (1). The apical surface of cuboidal and columnar epithelial cells commonly faces a luminal cavity and is characterized by the presence of numerous surface membrane elaborations referred to as microvilli. Microvilli greatly increase the apical surface area and, consequently, the number of transport and signaling proteins it contains, thereby enhancing the epithelial functional capacity. Absorptive epithelia such as kidney and intestine have their apical surface decorated with highly organized apical microvilli of uniform length and width. More dynamic and less organized structures are present in the epithelial cells of the placenta and the retinal pigment epithelium (RPE), 1 which perform endocytosis and phagocytosis, respectively. The basis of this morphological heterogeneity is poorly understood and is likely to be related to the specialized function and specific molecular composition of the ...

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Section: Discussionmentioning

confidence: 99%

Proteomic Characterization of Isolated Retinal Pigment Epithelium Microvilli

Bonilha

Bhattacharya

West

et al. 2004

Molecular & Cellular Proteomics

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“…Age-related changes including neuronal loss [23], gliosis [22] and deposition of ubiquitin-positive granules [9,16] have been demonstrated in the brain of dog. Liu et al [15] reported the age-related decrease of synaptic density in the cerebral cortex of humans.…”

Section: Discussionmentioning

confidence: 99%

Age-Related Changes in the Cochlea and Cochlear Nuclei of Dogs.

et al. 1998

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ABSTRACT. To study the underlying morphological changes of presbycusis, cochlea and cochlear nuclei from twenty three dogs, ranging in age from 3 days to 17 years, were examined histologically. Dogs used in this study were house dogs kept in an environment similar to that of humans. Four types of histological changes reported in human presbycusis, that is, loss of spiral ganglion cells, atrophy of the organ of Corti, atrophy of the stria vascularis, and thickening of the basilar membrane were observed in dogs. The changes were prominent at the base of the cochlea. Less intense changes were also observed in the apex of the cochlea. The degree of these changes appeared to progress as a function of age. All four types of changes with varied intensity were found in all dogs over 12 years old. In addition to the changes in the cochlea, cochlear nuclei changes including nerve cell loss, astrogliosis and ubiquitin deposition were found in dogs over 10 years old. Hearing dysfunction was accompanied by the morphological changes, though the degree of the hearing dysfunction did not always parallel to that of morphological changes. The morphological changes seen in the cochlea and cochlear nuclei of dogs were qualitatively and quantitatively similar to those reported in aged humans, indicating that otopathologic changes in the inner ear may be due to aging plus exposure to certain environmental ototoxic factors. -KEY WORDS: aging, canine, cochlea, cochlear nucleus, presbycusis.J. Vet. Med. Sci. 60(1): 41-48, 1998 ganglion neurons was responsible for hearing loss. These studies, however, were not designed to cover full anatomical regions in the cochlear pathology. The purpose of the present paper was to examine a wide variety of the agerelated morphological changes in the cochlea and cochlear nuclei of dogs reared in a similar environment to that of humans.

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“…Long-lasting neurogenesis occurs in humans as well; when OE was isolated from middle aged and elderly postmortem OE and grown in vitro , some newborn cells did express OMP, albeit at a low rate (Hahn et al, 2005). However, as in the VNO, the rate of proliferation in the OE also declines with age [mouse (Loo et al, 1996); guinea pig (Nakamura et al, 1998); and dog (Hirai et al, 1996)]. Similar to the VNO, during the first year of life in the rat OE, neurogenesis was shown to contribute largely to growth rather than replacement (Weiler and Farbman, 1997).…”

Section: The Effect Of Organismal Age On Neurogenesis In the Olfactormentioning

confidence: 99%

A lifetime of neurogenesis in the olfactory system

Brann¹,

Firestein²

2014

Front. Neurosci.

191

139

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Neurogenesis continues well beyond embryonic and early postnatal ages in three areas of the nervous system. The subgranular zone supplies new neurons to the dentate gyrus of the hippocampus. The subventricular zone supplies new interneurons to the olfactory bulb, and the olfactory neuroepithelia generate new excitatory sensory neurons that send their axons to the olfactory bulb. The latter two areas are of particular interest as they contribute new neurons to both ends of a first-level circuit governing olfactory perception. The vomeronasal organ and the main olfactory epithelium comprise the primary peripheral olfactory epithelia. These anatomically distinct areas share common features, as each exhibits extensive neurogenesis well beyond the juvenile phase of development. Here we will discuss the effect of age on the structural and functional significance of neurogenesis in the vomeronasal and olfactory epithelia, from juvenile to advanced adult ages, in several common model systems. We will next discuss how age affects the regenerative capacity of these neural stem cells in response to injury. Finally, we will consider the integration of newborn neurons into an existing circuit as it is modified by the age of the animal.

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Age‐related changes in the olfactory system of dogs

Cited by 53 publications

References 25 publications

Proteomic Characterization of Isolated Retinal Pigment Epithelium Microvilli

Proteomic Characterization of Isolated Retinal Pigment Epithelium Microvilli

Age-Related Changes in the Cochlea and Cochlear Nuclei of Dogs.

A lifetime of neurogenesis in the olfactory system

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