Neurogenesis in olfactory epithelium: loss and recovery of transepithelial voltage transients following olfactory nerve section

1981 ◽  
Vol 45 (3) ◽  
pp. 516-528 ◽  
Author(s):  
P. A. Simmons ◽  
T. V. Getchell
Keyword(s):  
Olfactory Bulb ◽  
Olfactory Epithelium ◽  
Olfactory Receptor ◽  
Time Course ◽  
Olfactory Nerve ◽  
Nerve Section ◽  
Retrograde Degeneration ◽  
Transepithelial Voltage ◽  
Receptor Neurons ◽  
Voltage Transients

1. Unilateral olfactory nerve section was performed on the salamander, Ambystoma tigrinum. Physiological recordings and macroscopic observations were made to investigate the physiological correlates of functional recovery in the olfactory epithelium. 2. Slow transepithelial voltage transients, Veog, evoked by several odorous stimuli systematically decreased in amplitude during the initial 7 days and were not recorded at 10 days following nerve section, suggesting retrograde degeneration of receptor neurons. This was true for negative Veog(-), and positive, Veog(+), response components. Responses obtained from the untreated contralateral side of each animal remained similar to nonaxotomized controls. 3. Progressive recovery of the voltage transients was studied at 24, 45, 80, and 100 days following nerve section. At all stages of recovery, the wave form and time course of the responses were characteristic for each stimulus. This suggested that the response properties of the newly differentiated neuronal population were similar to those of the mature population. 4. At 100 days, response amplitudes evoked by all stimuli were similar to control values at all recording sites on the epithelial surface. The simultaneous loss and recovery of positive and negative components of the Veog indicated that the sources of both are dependent on the presence of functionally mature olfactory receptor neurons. 5. Visual inspection indicated that the olfactory nerve was reconstituted and reconnected to the olfactory bulb between 30-60 days following transection. The fact that physiological activity was recorded in the epithelium prior to this event suggests that molecular recognition and sensory transduction are not dependent on connectivity with the olfactory bulb. 6. It is concluded that physiological recovery of the olfactory receptor cell population occurs following axotomy. The time course of recovery was consistent with morphological evidence (see Ref. 57), indicating that newly differentiated receptor neurons are derived from cells in the basal region of the epithelium and replace the population lost through retrograde degeneration.

Physiological activity of newly differentiated olfactory receptor neurons correlated with morphological recovery from olfactory nerve section in the salamander

1981 ◽  
Vol 45 (3) ◽  
pp. 529-549 ◽  
Author(s):  
P. A. Simmons ◽  
T. V. Getchell
Keyword(s):  
Olfactory Bulb ◽  
Spontaneous Activity ◽  
Histological Examination ◽  
Olfactory Epithelium ◽  
Olfactory Receptor ◽  
Receptor Cell ◽  
Olfactory Nerve ◽  
Olfactory Receptor Neurons ◽  
Nerve Section ◽  
Receptor Neurons

1. Extracellular unitary recordings were made from the olfactory epithelium of the salamander, Ambystoma tigrinum, at numerous time points following olfactory nerve section. Unitary response properties were correlated with histological examination of the same tissues. 2. At 10 days following nerve section, unitary activity was rarely recorded in all regions of the epithelium. Histological examination indicated that virtually the entire mature olfactory receptor cell population had undergone retrograde degeneration. Transneuronal degeneration was not observed in the olfactory bulb, although the olfactory nerve and glomerular layers were substantially reduced in size. 3. At subsequent times, unitary impulse activity gradually returned, consisting of both spontaneous activity and odor-evoked discharges. Anatomical recovery of the olfactory epithelium preceded that of the olfactory bulb. A positive correlation was found between neuronal differentiation in the olfactory epithelium and the recovery of receptor cell function. 4. Patterns of spontaneous activity, odor specificities, intensity-response functions, and adaptive properties studied in newly differentiated olfactory receptor neurons were indistinguishable from those observed in control units. This indicated that these properties were intrinsic to the receptor neurons. 5. Spontaneously active and responsive units were encountered prior to olfactory nerve connection with the bulb. It is concluded that receptor neurons pass through two phases of functional maturity: the first independent of bulbar contact and the second dependent on presumed synaptic contact with bulbar neurons.

scholarly journals Evidence of SARS-CoV2 entry protein ACE2 in the human nose and olfactory bulb

2020 ◽  
Author(s):  
M. Klingenstein ◽  
S. Klingenstein ◽  
P.H. Neckel ◽  
A. F. Mack ◽  
A. Wagner ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Olfactory Epithelium ◽  
Olfactory Receptor ◽  
Respiratory Epithelium ◽  
Olfactory Receptor Neurons ◽  
Basal Cells ◽  
Sustentacular Cells ◽  
Glandular Cells ◽  
Receptor Neurons ◽  
Human Nose

ABSTRACTUsually, pandemic COVID-19 disease, caused by SARS-CoV2, presents with mild respiratory symptoms such as fever, cough but frequently also with anosmia and neurological symptom. Virus-cell fusion is mediated by Angiotensin-Converting Enzyme 2 (ACE2) and Transmembrane Serine Protease 2 (TMPRSS2) with their organ expression pattern determining viral tropism. Clinical presentation suggests rapid viral dissemination to central nervous system leading frequently to severe symptoms including viral meningitis. Here, we provide a comprehensive expression landscape of ACE2 and TMPRSS2 proteins across human, post-mortem nasal and olfactory tissue. Sagittal sections through the human nose complemented with immunolabelling of respective cell types represent different anatomically defined regions including olfactory epithelium, respiratory epithelium of the nasal conchae and the paranasal sinuses along with the hardly accessible human olfactory bulb. ACE2 can be detected in the olfactory epithelium, as well as in the respiratory epithelium of the nasal septum, the nasal conchae and the paranasal sinuses. ACE2 is located in the sustentacular cells and in the glandular cells in the olfactory epithelium, as well as in the basal cells, glandular cells and epithelial cells of the respiratory epithelium. Intriguingly, ACE2 is not expressed in mature or immature olfactory receptor neurons and basal cells in the olfactory epithelium. Similarly ACE2 is not localized in the olfactory receptor neurons albeit the olfactory bulb is positive. Vice versa, TMPRSS2 can also be detected in the sustentacular cells and the glandular cells of the olfactory epithelium.Our findings provide the basic anatomical evidence for the expression of ACE2 and TMPRSS2 in the human nose, olfactory epithelium and olfactory bulb. Thus, they are substantial for future studies that aim to elucidate the symptom of SARS-CoV2 induced anosmia of via the olfactory pathway.

scholarly journals Evidence of SARS-CoV2 Entry Protein ACE2 in the Human Nose and Olfactory Bulb

2021 ◽  
pp. 1-10
Author(s):  
Moritz Klingenstein ◽  
Stefanie Klingenstein ◽  
Peter H. Neckel ◽  
Andreas F. Mack ◽  
Andreas P. Wagner ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Olfactory Epithelium ◽  
Olfactory Receptor ◽  
Respiratory Epithelium ◽  
Olfactory Receptor Neurons ◽  
Basal Cells ◽  
Sustentacular Cells ◽  
Glandular Cells ◽  
Receptor Neurons ◽  
Human Nose

Usually, pandemic COVID-19 disease, caused by SARS-CoV2, presents with mild respiratory symptoms such as fever, cough, but frequently also with anosmia and neurological symptoms. Virus-cell fusion is mediated by angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) with their organ expression pattern determining viral tropism. Clinical presentation suggests rapid viral dissemination to the central nervous system leading frequently to severe symptoms including viral meningitis. Here, we provide a comprehensive expression landscape of ACE2 and TMPRSS2 proteins across human postmortem nasal and olfactory tissue. Sagittal sections through the human nose complemented with immunolabelling of respective cell types represent different anatomically defined regions including olfactory epithelium, respiratory epithelium of the nasal conchae and the paranasal sinuses along with the hardly accessible human olfactory bulb. ACE2 can be detected in the olfactory epithelium as well as in the respiratory epithelium of the nasal septum, the nasal conchae, and the paranasal sinuses. ACE2 is located in the sustentacular cells and in the glandular cells in the olfactory epithelium as well as in the basal cells, glandular cells, and epithelial cells of the respiratory epithelium. Intriguingly, ACE2 is not expressed in mature or immature olfactory receptor neurons and basal cells in the olfactory epithelium. Similarly, ACE2 is not localized in the olfactory receptor neurons albeit the olfactory bulb is positive. Vice versa, TMPRSS2 can also be detected in the sustentacular cells and the glandular cells of the olfactory epithelium. Our findings provide the basic anatomical evidence for the expression of ACE2 and TMPRSS2 in the human nose, olfactory epithelium, and olfactory bulb. Thus, they are substantial for future studies that aim to elucidate the symptom of SARS-CoV2 induced anosmia via the olfactory pathway.

Time course of reinnervation of the olfactory bulb after transection of the primary olfactory nerve in the pigeon

1995 ◽  
Vol 683 (2) ◽  
pp. 159-163 ◽  
Author(s):  
Roger A. Jennings ◽  
C.Jane Hambright Keiger ◽  
James C. Walker
Keyword(s):  
Olfactory Bulb ◽  
Time Course ◽  
Olfactory Nerve

Disorders of the Cranial Nerves and Brainstem

2021 ◽  
pp. 851-861
Author(s):  
Kelly D. Flemming
Keyword(s):  
Olfactory Bulb ◽  
Olfactory Receptor ◽  
Cranial Nerves ◽  
Olfactory Nerve ◽  
Mitral Cell ◽  
Olfactory Cortex ◽  
Olfactory Receptor Cells ◽  
Receptor Cells ◽  
Clinical Disorders ◽  
Primary Olfactory Cortex

This chapter briefly repeats key anatomic characteristics and then reviews clinical disorders affecting each cranial nerve in addition to the brainstem. More specifically, this chapter covers cranial nerves I, V, VII, and IX through XII plus the brainstem. The olfactory nerve is a special visceral afferent nerve that functions in the sense of smell. The axons of the olfactory receptor cells within the nasal cavity extend through the cribriform plate to the olfactory bulb. These olfactory receptor cell axons synapse with mitral cells in the olfactory bulb. Mitral cell axons project to the primary olfactory cortex and amygdala. The olfactory cortex interconnects with various autonomic and visceral centers.

scholarly journals Adaptive integrate-and-fire model reproduces the dynamics of olfactory receptor neuron responses in a moth

2019 ◽  
Vol 16 (157) ◽  
pp. 20190246 ◽  
Author(s):  
Marie Levakova ◽  
Lubomir Kostal ◽  
Christelle Monsempès ◽  
Philippe Lucas ◽  
Ryota Kobayashi
Keyword(s):  
Olfactory Receptor ◽  
Time Course ◽  
Olfactory Receptor Neuron ◽  
Receptor Activation ◽  
Olfactory Receptor Neurons ◽  
Response Dynamics ◽  
Spike Threshold ◽  
Olfactory Stimuli ◽  
Receptor Neurons ◽  
The Brain

In order to understand how olfactory stimuli are encoded and processed in the brain, it is important to build a computational model for olfactory receptor neurons (ORNs). Here, we present a simple and reliable mathematical model of a moth ORN generating spikes. The model incorporates a simplified description of the chemical kinetics leading to olfactory receptor activation and action potential generation. We show that an adaptive spike threshold regulated by prior spike history is an effective mechanism for reproducing the typical phasic–tonic time course of ORN responses. Our model reproduces the response dynamics of individual neurons to a fluctuating stimulus that approximates odorant fluctuations in nature. The parameters of the spike threshold are essential for reproducing the response heterogeneity in ORNs. The model provides a valuable tool for efficient simulations of olfactory circuits.

Dendritic origin of late events in optical recordings from salamander olfactory bulb

1992 ◽  
Vol 68 (3) ◽  
pp. 786-806 ◽  
Author(s):  
A. R. Cinelli ◽  
B. M. Salzberg
Keyword(s):  
Olfactory Bulb ◽  
Time Course ◽  
Slow Component ◽  
Field Potential ◽  
Olfactory Nerve ◽  
Nerve Fibers ◽  
Dependent Manner ◽  
Gamma Aminobutyric Acid ◽  
Direct Stimulation ◽  
Compound Action

1. Optical recordings of membrane-potential changes were used to characterize the origin and properties of the electrical signals from the dendritic level in slices of the salamander olfactory bulb. 2. The optical events were correlated with field-potential waves recorded simultaneously. Both responses exhibited patterns similar to those found in other species. 3. Orthodromic stimulation evoked a compound action potential in the olfactory nerve fibers, followed by two additional principal waves (N1 and N2). These field-potential waves reflected excitatory postsynaptic potentials at the primary mitral/tufted and granule cell dendrites, respectively. 4. Extrinsic optical signals from horizontal slices stained with the pyrazo-oxonal dye RH-155 showed a characteristic sequence of depolarizing and hyperpolarizing events. All of the signals exhibited a wavelength dependence expected for this dye and were abolished in the presence of high K+ in the bath. 5. According to their time courses, depolarizing responses under normal recording conditions were divided into two components, fast and slow. Orthodromic stimuli evoked a fast presynaptic response that represents synchronous compound action potentials from olfactory nerve fibers. At subglomerular levels, additional fast responses could often be recorded at the peri/subglomerular level and in the mitral/tufted somata region. These postsynaptic responses partially coincided with the rising phase of a different depolarizing signal, a slow component characterized by its prolonged time course. 6. With orthodromic stimulation, this slow signal attained its largest amplitude in the zone between the glomeruli and the superficial part of the external plexiform layer (EPL). Antidromic stimuli evoked a signal with some similarities to the one evoked orthodromically, but originating in deeper EPL regions. 7. Slow components were characterized by their Ca dependence. Low Ca2+ medium, or calcium channel blockers, suppressed this optical component, whether evoked orthodromically, antidromically, or by direct stimulation. In addition, Ba2+ (2.5–3.6 mM) in the bath did not abolish these responses, suggesting that they do not reflect a glial depolarization in response to elevated extracellular K+ concentration ([K+]o). 8. Locally applied stimuli next to the glomerular layer elicited these signals in 5–10 microM tetrodotoxin (TTX) or in low extracellular Na+ concentration ([Na+]o) medium, but antidromic or orthodromic stimuli failed to evoke the response under these conditions. The sizes of the responses to local stimuli remained constant, but an increase in their duration was observed in either TTX or low [Na+]o. 9. gamma-Aminobutyric acid (GABA) and baclofen reduced the size of the slow components in a dose-dependent manner.(ABSTRACT TRUNCATED AT 400 WORDS)

Neuronal nitric oxide synthase-like immunoreactivity in olfactory epithelium throughout the life cycle of the sea lamprey, Petromyzon marinus L.

2000 ◽  
Vol 78 (3) ◽  
pp. 346-351 ◽  
Author(s):  
Hong N Hua ◽  
Aliya U Zaidi ◽  
Barbara S Zielinski
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Olfactory Epithelium ◽  
Olfactory Receptor ◽  
Petromyzon Marinus ◽  
Neuronal Nitric Oxide Synthase ◽  
Sea Lamprey ◽  
Olfactory Receptor Neurons ◽  
Receptor Neurons ◽  
Oxide Synthase

This study is the first to show that neuronal nitric oxide synthase-like immunoreactivity is located in the olfactory epithelium at all developmental stages of a vertebrate. Western immunoblotting of sea lamprey (Petromyzon marinus L.) olfactory mucosa with a monoclonal antibody against the NADPH-binding epitope of neuronal nitric oxide synthase showed that the molecular mass of this protein was 200 kDa. In the larval stage, neuronal nitric oxide synthase-like immunoreactivity was strongest in the basal region of the olfactory epithelium, the site of proliferating olfactory receptor neurons. This staining gradually diminished as the life cycle progressed. In the juvenile stage, the intensity of neuronal nitric oxide synthase-like immunoreactivity was striking in the wide cell bodies and dendrites on olfactory receptor neurons. These results confirm previous evidence that nitric oxide modulates development in the olfactory epithelium.

Functional properties of vertebrate olfactory receptor neurons

1986 ◽  
Vol 66 (3) ◽  
pp. 772-818 ◽  
Author(s):  
T. V. Getchell
Keyword(s):  
Olfactory Receptor ◽  
Olfactory Receptor Neuron ◽  
Olfactory Nerve ◽  
Sensory Transduction ◽  
Olfactory Receptor Neurons ◽  
Receptor Neuron ◽  
Olfactory Pathway ◽  
Receptor Neurons ◽  
Molecular Biological Techniques

The interaction of an odorant with the chemosensitive membrane of olfactory receptor neurons initiates a sequence of molecular and membrane events leading to sensory transduction, impulse initiation, and the transmission of sensory information to the brain. The main steps in this sequence are summarized in Figure 6. Several lines of evidence support the hypothesis that the initial molecular events and subsequent stages of transduction are mediated by odorant receptor sites and associated ion channels located in the membrane of the cilia and apical dendritic knob of the olfactory receptor neuron. Similarly, the membrane events associated with impulse initiation and propagation are mediated by voltage-gated channels located in the initial axonal segment and the axolemma. The ionic and electrical events associated with the proposed sequence have been characterized in general using a variety of experimental techniques. The identification, localization, and sequence of membrane events are consistent with the neurophysiological properties observed in specific regions of the bipolar receptor neuron. The influence of other cells in the primary olfactory pathway such as the sustentacular cells in the olfactory epithelium, the Schwann cells in the olfactory nerve, and the astrocytes in the olfactory nerve layer in the olfactory bulb on the physiological activity of the olfactory receptor neuron is an emerging area of research interests. The general principles derived from the experimental results described in this review provide only a framework that is both incomplete and of necessity somewhat speculative. As noted in the Introduction, the multidisciplinary study of the primary olfactory pathway is undergoing a renaissance of research interest. The application of modern biophysical, cell, and molecular biological techniques to the basic issues of odorant recognition and membrane excitability will clarify the speculations and lead to the establishment of new hypotheses. Three broad areas of research will benefit from such studies. First, the application of biophysical techniques will lead to a detailed characterization of the membrane properties and associated ion conductance mechanisms. Second, the isolation and biochemical characterization of intrinsic membrane and cytosolic proteins associated with odorant recognition, sensory transduction, and the subsequent electrical events will result from the utilization of cell and molecular biological techniques.(ABSTRACT TRUNCATED AT 400 WORDS)

Sign in / Sign up

Export Citation Format

Share Document