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 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).

Intracellular responses of identified rat olfactory bulb interneurons to electrical and odor stimulation

1990 ◽  
Vol 64 (3) ◽  
pp. 932-947 ◽  
Author(s):  
D. P. Wellis ◽  
J. W. Scott
Keyword(s):  
Electrical Stimulation ◽  
Olfactory Bulb ◽  
Granule Cell ◽  
Action Potentials ◽  
Granule Cells ◽  
Olfactory Nerve ◽  
Mitral Cell ◽  
Intracellular Recordings ◽  
Postsynaptic Potential ◽  
Stimulation Of

1. Intracellular recordings were made from 28 granule cells and 6 periglomerular cells of the rat olfactory bulb during odor stimulation and electrical stimulation of the olfactory nerve layer (ONL) and lateral olfactory tract (LOT). Neurons were identified by injection of horseradish peroxidase (HRP) or biocytin and/or intracellular response characteristics. Odorants were presented in a cyclic sniff paradigm, as reported previously. 2. All interneurons could be activated from a wide number of stimulation sites on the ONL, with distances exceeding their known dendritic spreads and the dispersion of nerve fibers within the ONL, indicating that multisynaptic pathways must also exist at the glomerular region. All types of interneurons also responded to odorant stimulation, showing a variety of responses. 3. Granule cells responded to electrical stimulation of the LOT and ONL as reported previously. However, intracellular potential, excitability, and conductance analysis suggested that the mitral cell-mediated excitatory postsynaptic potential (EPSP) is followed by a long inhibitory postsynaptic potential (IPSP). An early negative potential, before the EPSP, was also observed in every granule cell and correlated with component I of the extracellular LOT-induced field potential. We have interpreted this negativity as a "field effect," that may be diagnostic of granule cells. 4. Most granule cells exhibited excitatory responses to odorant stimulation. Odors could produce spiking responses that were either nonhabituating (response to every sniff) or rapidly habituating (response to first sniff only). Other granule cells, while spiking to electrical stimulation, showed depolarizations that did not evoke spikes to odor stimulation. These depolarizations were transient with each sniff or sustained across a series of sniffs. These physiological differences to odor stimulation correlated with granule cell position beneath the mitral cell layer for 12 cells, suggesting that morphological subtypes of granule cells may show physiological differences. Some features of the granule cell odor responses seem to correlate with some of the features we have observed in mitral/tufted cell intracellular recordings. Only one cell showed inhibition to odors. 5. Periglomerular (PG) cells showed a response to ONL stimulation that was unlike that found in other olfactory bulb neurons. There was a long-duration hyperpolarization after a spike and large depolarization or burst of spikes (20-30 ms in duration). Odor stimulation produced simple bursts of action potentials, Odor stimulation produced simple bursts of action potentials, suggesting that PG cells may simply follow input from the olfactory nerve.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Intraglomerular inhibition maintains mitral cell response contrast across input frequencies

2013 ◽  
Vol 110 (9) ◽  
pp. 2185-2191 ◽  
Author(s):  
Zuoyi Shao ◽  
Adam C. Puche ◽  
Michael T. Shipley
Keyword(s):  
Sensory Input ◽  
Olfactory Nerve ◽  
Mitral Cell ◽  
Spike Rate ◽  
Spike Burst ◽  
Frequency Independent ◽  
Tufted Cells ◽  
Current Area ◽  
Odor Signals

Odor signals are transmitted to the olfactory bulb by olfactory nerve (ON) synapses onto mitral/tufted cells (MTCs) and external tufted cells (ETCs); ETCs provide additional feed-forward excitation to MTCs. Both are strongly regulated by intraglomerular inhibition that can last up to 1 s and, when blocked, dramatically increases ON-evoked MC spiking. Intraglomerular inhibition thus limits the magnitude and duration of MC spike responses to sensory input. In vivo, sensory input is repetitive, dictated by sniffing rates from 1 to 8 Hz, potentially summing intraglomerular inhibition. To investigate this, we recorded MTC responses to 1- to 8-Hz ON stimulation in slices. Inhibitory postsynaptic current area (charge) following each ON stimulation was unchanged from 1 to 5 Hz and modestly paired-pulse attenuated at 8 Hz, suggesting there is no summation and only limited decrement at the highest input frequencies. Next, we investigated frequency independence of intraglomerular inhibition on MC spiking. MCs respond to single ON shocks with an initial spike burst followed by reduced spiking decaying to baseline. Upon repetitive ON stimulation peak spiking is identical across input frequencies but the ratio of peak-to-minimum rate before the stimulus (max-min) diminishes from 30:1 at 1 Hz to 15:1 at 8 Hz. When intraglomerular inhibition is selectively blocked, peak spike rate is unchanged but trough spiking increases markedly decreasing max-min firing ratios from 30:1 at 1 Hz to 2:1 at 8 Hz. Together, these results suggest intraglomerular inhibition is relatively frequency independent and can “sharpen” MC responses to input across the range of frequencies. This suggests that glomerular circuits can maintain “contrast” in MC encoding during sniff-sampled inputs.

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.

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.

Population abundance of the common hippopotamus Hippopotamus amphibius in the Haut Niger National Park, Republic of Guinea / Abondance de la population d'hippopotame commun Hippopotamus amphibius dans le Parc National du Haut Niger, République de Guinée

Mammalia ◽  
2006 ◽  
Vol 70 (1-2) ◽  
Author(s):  
David Brugière ◽  
Bakary Magassouba ◽  
Amidou Sylla ◽  
Halimou Diallo ◽  
Mamadou Sow
Keyword(s):  
National Park ◽  
Buffer Zone ◽  
Wet Season ◽  
Republic Of Guinea ◽  
Hippopotamus Amphibius ◽  
The Status ◽  
Grazing Area ◽  
The Common ◽  
The Republic

AbstractThe Republic of Guinea is thought to contain the largest population of common hippopotamus in West Africa. However, no systematic field survey has been carried out recently and the information available is limited to informal observations. To clarify the status of the common hippopotamus in Guinea, we carried out a biannual population survey along the section of the Niger River (the largest river in Guinea) within the Haut Niger National Park. We counted 93 hippopotamuses in 28 groups in the dry season and 77 hippopotamuses in 23 groups in the wet season. Mean group size and number of neonates did not change between the seasons. Hippopotomuses were more numerous along the river sections bordering uncultivated floodplains. This underlines the significance of this habitat (which is used as a grazing area) for conservation of this species. Haut Niger National Park is the most important protected area in Guinea for conservation of the common hippopotamus. Hippopotamus-human and -cattle conflicts in terms of floodplain use in the park's buffer zone should be closely monitored. Floodplain conversion to rice fields represents one of the most important threats to the long-term conservation of hippopotamus populations in Guinea.

scholarly journals Preventing crop raiding by the Vulnerable common hippopotamus Hippopotamus amphibius in Guinea-Bissau

Oryx ◽  
2016 ◽  
Vol 51 (2) ◽  
pp. 222-229 ◽  
Author(s):  
Luis M. González ◽  
Francisco G. D. Montoto ◽  
Tome Mereck ◽  
Junior Alves ◽  
José Pereira ◽  
...  
Keyword(s):  
Coastal Waters ◽  
Rice Fields ◽  
Crop Damage ◽  
Running Water ◽  
Rice Farmers ◽  
Guinea Bissau ◽  
Hippopotamus Amphibius ◽  
Electric Fencing ◽  
Effective Deterrent ◽  
The Common

AbstractGuinea-Bissau is host to the westernmost subpopulation of the common hippopotamus Hippopotamus amphibius, which is one of only two known populations inhabiting coastal waters. The presence of hippopotamuses causes conflict with rice farmers as a result of crop damage and the absence of effective measures to protect crops. To develop an effective method for protecting rice fields, we studied the patterns of access to flooded and rain-fed rice fields by hippopotamuses and assessed the effect of the installation of electric fences. Hippopotamuses were detected in 54% of the flooded fields (n = 100) and in 31.9% of the rain-fed fields (n = 91). They were detected more frequently in fields on offshore islands than on the mainland, in unfenced than in fenced fields, and in fields closer to running water. Hippopotamuses entered fenced flooded fields less frequently than unfenced, and were detected most frequently at the end of the rainy season and the start of the dry season, and in the period of vegetative stem growth. Electric fences were an effective deterrent and facilitated increased rice production. The maintenance and cost of the electric fencing were acceptable to farmers, and therefore the use of such fencing is recommended to resolve the conflict between hippopotamuses and farmers in Guinea-Bissau and in other areas with similar conditions.

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