scholarly journals In goldfish the discriminative ability for odours persists after reduction of the olfactory epithelium, and rapidly returns after olfactory nerve axotomy and crossing bulbs

2000 ◽  
Vol 355 (1401) ◽  
pp. 1219-1223 ◽  
Author(s):  
Hans Peter Zippel
Keyword(s):  
Amino Acid ◽  
Olfactory Epithelium ◽  
Functional Recovery ◽  
Olfactory System ◽  
Olfactory Nerve ◽  
Sensory Cells ◽  
Similar Concentration ◽  
Olfactory Bulbs ◽  
Discriminative Ability ◽  
Bilateral Lesions

Goldfish are ideal vertebrates for the study of regeneration within the peripheral and the central olfactory system. The present behavioural investigations studied the effects of bilateral lesions on the animals' ability to qualitatively discriminate two amino acids (107 -6 M) and their performance in two more difficult tasks: (i) rewarded amino acid applied in a lower concentration, and (ii) rewarded stimulus contaminated. A 50 and 85% reduction of the olfactory epithelium resulted in no recordable behavioural deficit. After axotomy of olfactory nerves and lateral olfactory tractotomy, fishes were anosmic for seven to ten days. Following replacement of sensory cells in the epithelium, and after regeneration of olfactory tract fibres a full functional recovery, i.e. a highly specific regeneration, was recorded. After three surgical modifications of the olfactory bulbs' position, (i) crossing olfactory tracts and bulbs, (ii) crossing tracts and turning bulbs, and (iii) turning bulbs upside down, a full functional recovery was recorded for amino-acid discrimination in a similar concentration. A permanent, and similar slight deficit was, however, found during application of different concentrations, and of contaminated stimuli when medial lateral halves of the bulb were in ‘incorrect’ position (i) and (iii), or olfactory bulbs were positioned in the vicinity of the contralateral epithelium (i) and (ii).

Histological Properties of Main and Accessory Olfactory Bulbs in the Common Hippopotamus

2017 ◽  
Vol 90 (3) ◽  
pp. 224-231 ◽  
Author(s):  
Daisuke Kondoh ◽  
Kenichi Watanabe ◽  
Kaori Nishihara ◽  
Yurie S. Ono ◽  
Kentaro G. Nakamura ◽  
...  
Keyword(s):  
Granule Cell ◽  
Olfactory System ◽  
Olfactory Nerve ◽  
Mitral Cell ◽  
Vomeronasal System ◽  
Olfactory Bulbs ◽  
Hippopotamus Amphibius ◽  
Cell Layers ◽  
The Common ◽  
Tufted Cells

The olfactory system of mammals comprises a main olfactory system that detects hundreds of odorants and a vomeronasal system that detects specific chemicals such as pheromones. The main (MOB) and accessory (AOB) olfactory bulbs are the respective primary centers of the main olfactory and vomeronasal systems. Most mammals including artiodactyls possess a large MOB and a comparatively small AOB, whereas most cetaceans lack olfactory bulbs. The common hippopotamus (Hippopotamus amphibius) is semiaquatic and belongs to the order Cetartiodactyla, family Hippopotamidae, which seems to be the closest extant family to cetaceans. The present study evaluates the significance of the olfactory system in the hippopotamus by histologically analyzing the MOB and AOB of a male common hippopotamus. The MOB comprised six layers (olfactory nerve, glomerular, external plexiform, mitral cell, internal plexiform, and granule cell), and the AOB comprised vomeronasal nerve, glomerular, plexiform, and granule cell layers. The MOB contained mitral cells and tufted cells, and the AOB possessed mitral/tufted cells. These histological features of the MOB and the AOB were similar to those in most artiodactyls. All glomeruli in the AOB were positive for anti-Gαi2, but weakly positive for anti-Gαo, suggesting that the hippopotamus vomeronasal system expresses vomeronasal type 1 receptors with a high affinity for volatile compounds. These findings suggest that the olfactory system of the hippopotamus is as well developed as that of other artiodactyl species and that the hippopotamus might depend on its olfactory system for terrestrial social communication.

scholarly journals EFFECTS OF INTRANASAL BACTERIAL ENDOTOXIN ADMINISTRATION ON EXPRESSION OF ALPHA-SYNUCLEIN IN PERIPHERAL STRUCTURES OF THE OLFACTORY SYSTEM

2019 ◽  
Vol 19 (1S) ◽  
pp. 103-104
Author(s):  
T N Sergeyeva ◽  
K S Sergeyeva
Keyword(s):  
Olfactory System ◽  
Neuronal Damage ◽  
Early Stage ◽  
Olfactory Nerve ◽  
Alpha Synuclein ◽  
Dopamine Neurons ◽  
Chemical Agent ◽  
Olfactory Bulbs ◽  
Dopamine Content ◽  
The Central Nervous System

The involvement of olfactory dysfunction led to the proposal of ‘the olfactory vector hypothesis’ to explain both olfactory losses and the etiology of idiopathic Parkinson disease (PD) as a result of the transit of an environmental virus or chemical agent that enters the central nervous system (CNS) via the nose, activating the glial response of the brain that may lead to dopamine neuronal damage. Previously created chronic, progressive a mouse model of PD by intranasal instillation of a LPS displayed several key features of early-stage PD: a progressive hypokinesia, selective loss of dopamine neurons, a reduction in striatal dopamine content, and α-synuclein (α-syn) accumulation and aggregation in the substance nigra. Other PD model based on nasal inoculation with α-syn aggregates also expressed parkinsonian-like behavioral and immunological features.We suggested that intranasal administration of LPS might cause an increase in expression and misfolding of a-syn in olfactory receptor cells that are projected into olfactory bulbs. We observed an increase in the expression of the native and phosphorylated forms of immunoreactive a-syn in olfactory cells, olfactory nerve and olfactory bulbs where, in addition, activated glial cells were observed. The findings suggest that bacterial antigens can cause parkinsonian-like features both by inducing a glial neuroinflammatory response and by increasing the production of phosphorylated a-syn in peripheral structures of the olfactory system.

Adenovirus-Mediated Gene Transfer in Olfactory Epithelium and Olfactory Bulb: A Long-Term Study

2005 ◽  
Vol 114 (8) ◽  
pp. 629-633 ◽  
Author(s):  
Kiyoshi Doi ◽  
Ken-Ichi Nibu ◽  
Haruhiko Ishida ◽  
Haruo Okado ◽  
Toshio Terashima
Keyword(s):  
Gene Transfer ◽  
Olfactory Epithelium ◽  
Adenoviral Vector ◽  
Olfactory Nerve ◽  
Lacz Gene ◽  
Long Term Effects ◽  
Olfactory Bulbs ◽  
Long Term Study ◽  
Receptor Neurons

Objectives: We sought to study the spatiotemporal gene expression mediated by adenoviral vector in the olfactory pathways. Methods: The replication-defective adenoviral vector AxCALacZ, which encodes the enzyme Escherichia coli β-galactosidase, was applied to mouse olfactory epithelium by intranasal instillation. Results: The LacZ gene product, β-galactosidase, was expressed not only in the olfactory receptor neurons and their axons, but also in the olfactory bulbs. The first evidence of anterograde labeling was observed at postinfection day (PID) 2. At PID 3, β-galactosidase was strongly expressed in olfactory nerve axons, as well as their terminal glomeruli, in the olfactory bulbs. β-Galactosidase expression persisted up to PID 90, and there was a significant decrease in the number of labeled neurons at PID 30. Conclusions: These results suggest possible long-term effects of adenovirus-mediated gene transfer on the olfactory neurons, as well as the olfactory bulbs.

scholarly journals Olfactory sensitivity to changes in environmental [Ca(2+)] in the marine teleost Sparus aurata

2000 ◽  
Vol 203 (24) ◽  
pp. 3821-3829 ◽  
Author(s):  
P.C. Hubbard ◽  
E.N. Barata ◽  
A.V. Canario
Keyword(s):  
Olfactory Epithelium ◽  
Olfactory System ◽  
Sea Water ◽  
Sparus Aurata ◽  
Specific Effect ◽  
Olfactory Nerve ◽  
Olfactory Response ◽  
Hill Coefficient ◽  
Gilthead Seabream ◽  
Continuous Exposure

Estuarine and/or migratory teleosts may experience large and rapid changes in external [Ca(2+)]. Previous studies have largely centred on the physiological mechanisms that maintain a constant plasma [Ca(2+)] in the face of such external fluctuations, but little work has been directed to examining how these changes may originally be detected. We present evidence that the olfactory system of the gilthead seabream (Sparus aurata) is highly sensitive to reductions in environmental [Ca(2+)] and suggest a possible mechanism by which this may be mediated. Multi-unit extracellular recordings were made from the olfactory nerve of Sparus aurata while the [Ca(2+)] of artificial sea water flowing over the olfactory epithelium was varied from 10 to 0 mmol l(−)(1). Reductions in [Ca(2+)] caused a large, non-accommodating increase in the firing rate of the olfactory nerve (apparent IC(50)=1.67+/−0.26 mmol l(−)(1), apparent Hill coefficient=−1.22+/−0.14; means +/− s.e.m., N=6). This response was not due to the concomitant reduction in osmolality and was specific for Ca(2+). During continuous exposure of the olfactory epithelium to Ca(2+)-free sea water, the apparent IC(50) and Hill coefficient in response to increases in [Ca(2+)] were 0.48+/−0.14 mmol l(−)(1) and −0.76+/−0.16 (means +/− s.e.m., N=6), respectively, suggesting an adaptation of the Ca(2+)-sensing system to low-[Ca(2+)] environments. Ca(2+) is intimately involved in signal transduction in the olfactory receptor neurones, but our data support a true olfactory response, rather than a non-specific effect to lowering of external [Ca(2+)]. The absence of Ca(2+) from sea water only partially and temporarily blunted the olfactory response to the odorant l-serine; the response amplitude recovered to control levels within 20 min. This suggests that the olfactory system in general is able to adapt to low-[Ca(2+)] environments. We suggest that the Ca(2+)sensitivity is mediated by an extracellular Ca(2+)-sensing receptor similar to the recently characterized mammalian Ca(2+)-sensing receptor.

Ultrastructural analysis of unique glycoconjugates in the rat olfactory system

1992 ◽  
Vol 50 (1) ◽  
pp. 890-891
Author(s):  
James E. Crandall ◽  
Linda C. Hassinger ◽  
Gerald A. Schwarting
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Monoclonal Antibodies ◽  
Olfactory System ◽  
Olfactory Bulbs ◽  
Temporal And Spatial Patterns ◽  
Carbohydrate Epitopes ◽  
Olfactory Systems ◽  
Temporal And Spatial ◽  
Cell Surface Glycoconjugates

Cell surface glycoconjugates are considered to play important roles in cell-cell interactions in the developing central nervous system. We have previously described a group of monoclonal antibodies that recognize defined carbohydrate epitopes and reveal unique temporal and spatial patterns of immunoreactivity in the developing main and accessory olfactory systems in rats. Antibody CC2 reacts with complex α-galactosyl and α-fucosyl glycoproteins and glycolipids. Antibody CC1 reacts with terminal N-acetyl galactosamine residues of globoside-like glycolipids. Antibody 1B2 reacts with β-galactosyl glycolipids and glycoproteins. Our light microscopic data suggest that these antigens may be located on the surfaces of axons of the vomeronasal and olfactory nerves as well as on some of their target neurons in the main and accessory olfactory bulbs.

Olfactory mucosal and neural responses in the frog

1962 ◽  
Vol 203 (2) ◽  
pp. 353-358 ◽  
Author(s):  
Maxwell Mark Mozell
Keyword(s):  
Stimulus Intensity ◽  
Olfactory Epithelium ◽  
Flow Rate ◽  
Olfactory Nerve ◽  
Neural Responses ◽  
Criterion Measure ◽  
Repeated Stimulation ◽  
Two Measures ◽  
Electrophysiological Technique

A comparatively recent electrophysiological technique for studying peripheral olfactory events is to record sustained negative potentials from the olfactory epithelium. This method is rapidly replacing the older technique of recording multifiber discharges from the olfactory nerve or bulb. Therefore, the extent to which the results from the two methods correlate with each other was studied by simultaneously recording from the nerve and from the mucosa under several conditions. Although most often parallel, some differences between the two measures were found. Their response maxima did not always temporally coincide. Their amplitudes did not always correlate. Certain stimuli reduced subsequent mucosal responses but not the neural. Repeated stimulation sometimes produced similar differences. Finally, the two responses were not linearly related as a function of stimulus intensity or flow rate. However, for reasons discussed, it is difficult to conclude that these discrepancies necessarily reflect unfavorably upon the reliability of the mucosal potential as the criterion measure of peripheral olfactory activity. Nevertheless, the mucosal potential should not be accepted unequivocally as such a criterion measure until it is more thoroughly understood.

scholarly journals Extinction reverses olfactory fear-conditioned increases in neuron number and glomerular size

2015 ◽  
Vol 112 (41) ◽  
pp. 12846-12851 ◽  
Author(s):  
Filomene G. Morrison ◽  
Brian G. Dias ◽  
Kerry J. Ressler
Keyword(s):  
Olfactory Bulb ◽  
Learning And Memory ◽  
Olfactory Epithelium ◽  
Olfactory System ◽  
Structural Changes ◽  
Freezing Behavior ◽  
Extinction Training ◽  
Odor Stimulus ◽  
Main Olfactory Epithelium ◽  
Odor Learning

Although much work has investigated the contribution of brain regions such as the amygdala, hippocampus, and prefrontal cortex to the processing of fear learning and memory, fewer studies have examined the role of sensory systems, in particular the olfactory system, in the detection and perception of cues involved in learning and memory. The primary sensory receptive field maps of the olfactory system are exquisitely organized and respond dynamically to cues in the environment, remaining plastic from development through adulthood. We have previously demonstrated that olfactory fear conditioning leads to increased odorant-specific receptor representation in the main olfactory epithelium and in glomeruli within the olfactory bulb. We now demonstrate that olfactory extinction training specific to the conditioned odor stimulus reverses the conditioning-associated freezing behavior and odor learning-induced structural changes in the olfactory epithelium and olfactory bulb in an odorant ligand-specific manner. These data suggest that learning-induced freezing behavior, structural alterations, and enhanced neural sensory representation can be reversed in adult mice following extinction training.

Differential and overlapping expression patterns of X-dll3 and Pax-6 genes suggest distinct roles in olfactory system development of the African clawed frog Xenopus laevis

2001 ◽  
Vol 204 (12) ◽  
pp. 2049-2061 ◽  
Author(s):  
Marie-Dominique Franco ◽  
Michael P. Pape ◽  
Jennifer J. Swiergiel ◽  
Gail D. Burd
Keyword(s):  
Xenopus Laevis ◽  
Expression Pattern ◽  
Olfactory Epithelium ◽  
Olfactory System ◽  
De Novo ◽  
System Development ◽  
Expression Patterns ◽  
Basal Cells ◽  
Olfactory Placode ◽  
Water Borne

SUMMARY In Xenopus laevis, the formation of the adult olfactory epithelium involves embryonic, larval and metamorphic phases. The olfactory epithelium in the principal cavity (PC) develops during embryogenesis from the olfactory placode and is thought to respond to water-borne odorants throughout larval life. During metamorphosis, the PC undergoes major transformations and is exposed to air-borne odorants. Also during metamorphosis, the middle cavity (MC) develops de novo. The olfactory epithelium in the MC has the same characteristics as that in the larval PC and is thought to respond to water-borne odorants. Using in situ hybridization, we analyzed the expression pattern of the homeobox genes X-dll3 and Pax-6 within the developing olfactory system. Early in development, X-dll3 is expressed in both the neuronal and non-neuronal ectoderm of the sense plate and in all cell layers of the olfactory placode and larval PC. Expression becomes restricted to the neurons and basal cells of the PC by mid-metamorphosis. During metamorphosis, X-dll3 is also expressed throughout the developing MC epithelium and becomes restricted to neurons and basal cells at metamorphic climax. This expression pattern suggests that X-dll3 is first involved in the patterning and genesis of all cells forming the olfactory tissue and is then involved in neurogenesis or neuronal maturation in putative water- and air-sensing epithelia. In contrast, Pax-6 expression is restricted to the olfactory placode, larval PC and metamorphic MC, suggesting that Pax-6 is specifically involved in the formation of water-sensing epithelium. The expression patterns suggest that X-dll3 and Pax-6 are both involved in establishing the olfactory placode during embryonic development, but subtle differences in cellular and temporal expression patterns suggest that these genes have distinct functions.

Physiological Evidence for the Discrimination ofl-Arginine From Structural Analogues by the Zebrafish Olfactory System

1999 ◽  
Vol 82 (6) ◽  
pp. 3160-3167 ◽  
Author(s):  
D. L. Lipschitz ◽  
W. C. Michel
Keyword(s):  
Amino Acid ◽  
Olfactory System ◽  
Basic Amino Acid ◽  
Chain Structure ◽  
Sensory Epithelium ◽  
Amino Groups ◽  
Electrophysiological Recordings ◽  
Cross Adaptation ◽  
Receptor Neurons ◽  
Activity Dependent

Although it is generally assumed that fish are capable of discriminating amino acid odorants on the basis of differences in side-chain structure, less is known about their ability to discriminate amino acids with modifications to α-carboxyl and α-amino groups. In this study, the ability of the zebrafish olfactory system to detect and presumably discriminate analogues of the basic amino acid Arg was assessed, by using cross-adaptation and activity-dependent labeling techniques. Electrophysiological recordings established that esterification (l-arginine methyl ester; AME) or deletion (agmatine or amino-4-guanidobutane; AGB) of the α-carboxyl group yielded odorants more potent than Arg, whereas deletion of the α-amino group (l-argininic acid; AA) yielded a less potent analogue. In cross-adaptation experiments, no test-competitor odorant combination yielded complete cross-adaptation, suggesting the detection of these Arg analogues by multiple odorant receptors (ORs) with partially nonoverlapping specificities. Activity-dependent immunocytochemical labeling of olfactory receptor neurons supported this conclusion. AGB, an ion-channel–permeant probe (and odorant), labeled 4.9 ± 0.4% ( n = 24) of sensory epithelium, whereas the addition of Arg, 1-ethylguanidine sulfate, l-α-amino-β-guanidinopropionate, or AME to AGB resulted in a significant elevation of labeling (8–14%). This study provides evidence that the olfactory system has the potential to discriminate among amino acid odorants with modified α-carboxyl and α-amino groups.

Olfactory epithelium ontogenesis and function in postembryonic North American Bullfrog (Rana (Lithobates) catesbeiana) tadpoles

2020 ◽  
Vol 98 (6) ◽  
pp. 367-375 ◽  
Author(s):  
J.L. Heerema ◽  
S.J. Bogart ◽  
C.C. Helbing ◽  
G.G. Pyle
Keyword(s):  
Olfactory Epithelium ◽  
North American ◽  
Olfactory System ◽  
Postembryonic Development ◽  
Acid Mixture ◽  
Epithelial Surface ◽  
American Bullfrog ◽  
Olfactory Stimuli ◽  
And Function ◽  
Lithobates Catesbeiana

During metamorphosis, the olfactory system remodelling in anuran tadpoles — to transition from detecting waterborne odorants to volatile odorants as frogs — is extensive. How the olfactory system transitions from the larval to frog form is poorly understood, particularly in species that become (semi-)terrestrial. We investigated the ontogeny and function of the olfactory epithelium of North American Bullfrog (Rana (Lithobates) catesbeiana Shaw, 1802) tadpoles at various stages of postembryonic development. Changes in sensory components observable at the epithelial surface were examined by scanning electron microscopy. Functionality of the developing epithelium was tested using a neurophysiological technique (electro-olfactography (EOG)), and behaviourally, using a choice maze to assess tadpole response to olfactory stimuli (algae extract, amino acids). The youngest (premetamorphic) tadpoles responded behaviourally to an amino acid mixture despite having underdeveloped olfactory structures (cilia, olfactory knobs) and no EOG response. The consistent appearance of olfactory structures in older (prometamorphic) tadpoles coincided with reliably obtaining EOG responses to olfactory stimuli. However, as tadpoles aged further, and despite indistinguishable differences in sensory components, behavioural- and EOG-based olfactory responses were drastically reduced, most strongly near metamorphic climax. This work demonstrates a more complex relationship between structure and function of the olfactory system during tadpole life history than originally thought.

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