摘要:

AbstractThis paper presents electron‐microscopic observations on biopsies of the olfactory mucosae of several classes of patients with smell disorders: 1) patients with loss of smell function following head injury (post‐traumatic anosmics or hyposmics); 2) patients with loss of smell function following severe head colds and/or sinus infections (post‐viral olfactory dysfunction, or PVOD); and 3) patients that have lacked smell function since birth (congenital anosmics). Of these, the traumatic anosmics' olfactory epithelia were quite disorganized; the orderly arrangement of supporting cells, ciliated olfactory receptor neurons, microvillar cells, and basal cells was disrupted. Although many somata of ciliated olfactory receptors were present, few of their dendrites reached the epithelial surface. The few olfactory vesicles present usually lacked olfactory cilia. The postviral anosmics, too, had a greatly reduced number of intact ciliated olfactory receptor neurons, and most of those present were aciliate. The post‐viral hyposmics had a larger population of intact, ciliated olfactory receptor cells. In the seven cases of congenital anosmia studied, no biopsies of olfactory epithelium were obtained, indicating the olfactory epithelium is either absent—or greatly reduced in area—in these individuals. © 1992 Wil

ISSN:1059-910X    

DOI:10.1002/jemt.1070230202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe mucus at the surface of the olfactory mucosa constitutes the milieu in which perireceptor events associated with olfactory transduction occur. In this review, the ultrastructure of olfactory mucus and of the secretory cells that synthesize and secrete olfactory mucus in the vertebrate olfactory mucosa is described. Bowman's glands are present in the olfactory mucosa of all vertebrates except fish. They consist of acini, which may contain mucous or serous cells or both, and ducts that traverse the olfactory epithelium to deliver secretions to the epithelial surface. Sustentacular cells are present in the olfactory epithelium of all vertebrates. In fish, amphibia, reptiles, and birds, they are secretory; in mammals, they generally are considered to be “nonsecretory,” although they may participate in the regulation of the mucous composition through micropinocytotic secretion and uptake. Goblet cells occur in the olfactory epithelium of fish and secrete a mucous product.Secretion from Bowman's glands and vasomotor activity in the olfactory mucosa are regulated by neural elements extrinsic to the primary olfactory neurons. Nerve fibers described in early anatomical studies and characterized by immunohistochemical studies contain a variety of neuroactive peptides and have several targets within the olfactory mucosa. Ultrastructural studies of nerve terminals in the olfactory mucosa have demonstrated the presence of adrenergic, cholinergic and peptidergic input to glands, blood vessels, and melanocytes in the lamina propria and of peptidergic terminals in the olfactory epithelium. The neural origins of the extrinsic nerve fibers and terminals are the trigeminal, terminal, and autonomic systems. © 1992 Wiley‐Lis

ISSN:1059-910X    

DOI:10.1002/jemt.1070230203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractMammalian olfactory neurons possess a well‐developed system of endocytic vesicles, endosomes, and lysosomes in their dendrites and perikarya. Vomeronasal neurons are similar and also contain much perikaryal agranular endoplasmic reticulum (AER). Olfactory supporting cells contain endocytic vesicles and endosomes associated closely with abundant fenestrated AER, and vesicles and numerous large dense vacuoles are present basally. Vomeronasal supporting cells have little AER, and few dense vacuoles occur in their bases. In olfactory neurons, ultrastructural tracers (0.08% horseradish peroxidase, thorium dioxide, ferritin) are endocytosed by olfactory receptor endings and transported to the cell body, where their movement is halted in lysosomes. Higher concentrations (1%) of horseradish peroxidase penetrate olfactory receptor plasma membranes and intercellular junctions. In olfactory supporting cells, endocytosed tracers pass through endosomes to accumulate in dense basal vacuoles. These observations indicate that olfactory sensory membranes are rapidly cycled and that endocytosed materials are trapped within the epithelium. It is proposed that in the olfactory epithelium, endocytosis presents redundant odorants to the enzymes of the supporting cell AER to prevent their accumulation, whereas in the vomeronasal epithelium the receptor cells carry out this activity. © 1992 Wiley‐Liss,

ISSN:1059-910X    

DOI:10.1002/jemt.1070230204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe olfactory neuron is specialized along its length into highly determined morphological regions. These regions include the dendritic cilia, dendritic vesicle, dendritic shaft proper, perikaryon, axon, zone of transition where the axon widens as it approaches its termination, and the axon terminal. Except for the zone of transition and the terminal, characteristic populations of microtubules occur in these compartments. In the olfactory vesicle, three discrete microtubule organizing centers (MTOCs) nucleate microtubules: the basal body, the lateral foot associated with the body, and dense masses of nearby material. Little is known about MTOCs elsewhere in the neuron, although the polarity of the axonal microtubules indicate that they originate at or near the perikaryon. An attempt is made to summarize what is known of the origin, structure, distribution, and function of microtubules in vertebrate olfactory neurons, which are useful model systems in which to study microtubules. Information about olfactory neuron microtubules may be applicable to neurons in general (e.g., the discovery that axons contain microtubules of uniform polarity was first made in the olfactory neuron) or to microtubules in other eukaryotic cells. © 1992 Wiley‐Liss, I

ISSN:1059-910X    

DOI:10.1002/jemt.1070230205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe localization of Ca++‐independent cell adhesion molecules (CAMS) in the developing and mature olfactory epithelium and bulb is reviewed. The CAMs included in this article are the neural cell adhesion molecule (N‐CAM), the 180 kD component of N‐CAM (N‐CAM 180), the embryonic form of N‐CAM (E‐N‐CAM), L1 glycoproteins, J1 glycoproteins, and the adhesion molecule on glia (AMOG). In addition, the expression of the L2‐HNK‐1 carbohydrate epitope, shared by N‐CAM, L1, J1 and myelin‐associated glycoprotein (MAG) in the adult olfactory epithelium and bulb has also been documented. For the localization of these molecules at the light and electron microscopic levels, immunocytochemical techniques were used and are described in detail.During development and organogenesis, the olfactory system exhibits a pattern of CAM expression similar to the general pattern described for the developing nervous system. In the adult olfactory system, however, a significant retention of CAMs characteristic for developmental and morphogenetic processes, such as E‐N‐CAM, AMOG, as well as the high molecular weight components of J1 glycoproteins, can be observed. The retention of these embryonic features are most likely associated with the cell turnover and high plasticity of this system. Moreover, the predominance of N‐CAM 180 with respect to other components of N‐CAM, as well as the absence of the L2/HNK‐1 carbohydrate epitope, are also particular traits of the primary olfactory system which could be associated with its exceptional pro

ISSN:1059-910X    

DOI:10.1002/jemt.1070230206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractIn vitro methods have been used to study several aspects of development of olfactory epithelium. In this paper, the value of growing olfactory tissue in explant cultures is reviewed and some experiments are reported on the identification of lectin receptors on olfactory axons by the use of lectin‐gold complexes. Both concanavalin A‐gold (con A‐gold) and wheat germ agglutinin‐gold consistently decorated olfactory axons in explant cultures. Con A‐gold also bound to the tips of growth cone filopodia, suggesting the glycoconjugate molecules containing α‐methyl‐pyranoside are important in adherence of growth cones to their substrate. The wide range in density of lectin‐gold particles suggested that axons, and the sensory cells from which they arise, are not a uniform population, i.e., they have different molecular fingerprints. This was supported by the observation that soybean agglutinin‐gold stained some axons very well, but others remained unstained. Peanut agglutinin did not bind to any axons. © 1

ISSN:1059-910X    

DOI:10.1002/jemt.1070230207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractBinding of colloidal gold‐conjugated lectins was studied in cilia and microvilli of rat olfactory and respiratory epithelia. This was done in sections of rapidly frozen, freeze‐substituted specimens embedded in Lowicryl K11M or, for wheat germ agglutinin (WGA) alone, in deep‐etched replicas. Olfactory dendritic endings and cilia labeled with WGA and faintly with soybean agglutinin (SBA); olfactory supporting cell microvilli bound onlyDolichos biflorusagglutinin (DBA). Microvilli of an infrequent cell bound peanut agglutinin (PNA), SBA, and WGA. These microvilli labeled more strongly with the last two lectins than the olfactory cilia. Respiratory cilia bound WGA and, somewhat more weakly, PNA; microvilli of ciliated respiratory cells bound all four lectins. Visualization of specific labeling improved after preincubation of sections with neuraminidase, except for DBA where lectin binding was abolished. PNA labeling was seen only after neuraminidase preincubation. The densities of membrane surface particles that labeled with WGA corresponded with those of fracture plane particles in a quantitative freeze‐fracture, deepetch analysis. Therefore, a considerable fraction of the WGA‐bound particles could reflect transmembrane proteins in olfactory dendritic endings and cilia and in respiratory cilia. The possible nature of these particles is discussed. © 1992 Wiley

ISSN:1059-910X    

DOI:10.1002/jemt.1070230208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

ISSN:1059-910X    

DOI:10.1002/jemt.1070230209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

ISSN:1059-910X    

DOI:10.1002/jemt.1070230201

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY