Olfactory Marker Protein
Olfactory Mucosa
Olfactory Bulb
Olfactory Receptor Neurons
Methyl n-Butyl Ketone
Olfactory Nerve
Nerve Tissue Proteins
Odors
The vomeronasal organ of the male ferret. (1/76)
The vomeronasal organ (VNO) is known to play a major role in sexual behavior in many mammals. This study is the first report that the adult male ferret has a VNO, which is considerably smaller and morphologically different from the usually crescent-shaped epithelium in several mammalian species, particularly rodents. There were no differences in the size or structure of the ferret VNO between the mating season in spring and the sexually quiescent season in autumn, although plasma testosterone, testis size and brain size are dramatically increased in spring and behavior changes significantly. The histological data suggest that the VNO might be not as important a structure in male ferret sexual behavior as in rodents. (+info)A method for maintaining odor-responsive adult rat olfactory receptor neurons in short-term culture. (2/76)
We report a culture system requiring the addition of freshly made ascorbic acid to the medium, that supports the short-term survival of adult rat olfactory receptor neurons. The cultured neurons exhibit typical voltage-gated currents and are responsive to application of odorants. (+info)Targeted deletion of a cyclic nucleotide-gated channel subunit (OCNC1): biochemical and morphological consequences in adult mice. (3/76)
The olfactory cyclic nucleotide-gated channel subunit 1 (OCNC1) is required for signal transduction in olfactory receptor cells. To further investigate the role of this channel in the olfactory system, the biochemical and morphological consequences of targeted disruption of OCNC1 were investigated in adult mice. Null as compared to wild-type mice had smaller olfactory bulbs, suggesting compromised development of the central target of the receptor cells. Ectopic olfactory marker protein (OMP)-stained fibers localized to the external plexiform layer reflected the relative immaturity of the olfactory bulb in the null mice. The olfactory epithelium of the knock-out mouse was thinner and showed lower expression of olfactory marker protein and growth-associated protein 43, indicating decreases in both generation and maturation of receptor cells. Tyrosine hydroxylase (TH) expression in the olfactory bulb, examined as a reflection of afferent activity, was reduced in the majority of periglomerular neurons but retained in atypical or "necklace" glomeruli localized to posterior aspects of the olfactory bulb. Double label studies demonstrated that the remaining TH-immunostained neurons received their innervation from a subset of receptor cells previously shown to express a phosphodiesterase that differs from that found in most receptor cells. These data indicate that expression of OCNC1 is required for normal development of the olfactory epithelium and olfactory bulb. The robust expression of TH in some periglomerular cells in the OCNC1-null mice suggests that receptor cells innervating these glomeruli may use an alternate signal transduction pathway. (+info)Immunocytochemical characteristics of cells and fibers in the nasal mucosa of young and adult macaques. (4/76)
The mammalian nasal cavity is lined by an olfactory mucosa (OM) and a respiratory mucosa (RM). The principal OM cell type is the olfactory receptor neuron (ORN). However, little is known about ORNs in the life histories of primates. The RM, similar to the RM in the tracheobronchial tract (TBT), is dominated by ciliated columnar cells. Neuroendocrine cells (NECs) are essential in the TBT; little is known about nasal NECs. This study examined the immunolabeling characteristics of primate OM and RM for three important proteins-calretinin (CR), olfactory marker protein (OMP), and protein gene product 9.5 (PGP). Tissues from newborn to 15-year-old macaques were analyzed to determine the expression of these proteins during various stages of development. Standard immunocytochemistry on aldehyde-fixed tissues was applied, utilizing the avidin-biotin peroxidase (ABC) method. Immuno-electron microscopy confirmed the immunoreactive cell types. ORNs were immunoreactive for CR, OMP, and PGP at all ages studied. Immunoreactivity for PGP also was displayed in a subset of ciliated, columnar epithelial cells in the RM and in an extensive network of subepithelial fibers spread throughout both mucosae. The results suggest that macaque ORNs express three important proteins over a wide life history, and that the macaque may be a reliable model for studying primate/human olfaction during aging. The PGP-labeling results also suggest that the macaque nasal peptidergic fibers express PGP and that the respiratory epithelium contains NECs with labeling characteristics similar to those in the TBT. (+info)Evolution of alachlor-induced nasal neoplasms in the Long-Evans rat. (5/76)
The chloracetanilide herbicide alachlor (2-chloro-2',6-diethyl-N-(methoxymethyl)-acetanilide) induces nasal neoplasms in rats following chronic dietary exposure. The present study sought to identify the cellular origin and mechanisms of tumor induction and progression. Male Long-Evans rats were fed alachlor (0 or 126 mg/kg/day) beginning at 6 weeks of age. Following 1 month of alachlor ingestion, neither histological abnormalities nor enhanced cell division (assessed by BrdU incorporation) occurred in any region of the nasal cavity. Six months of alachlor exposure resulted in proliferation of basal and nonbasal cells in the olfactory mucosa while inducing nasal masses in 7 of 15 animals. Tumors ranged from dysplastic plaques to polypoid adenomas and originated in the olfactory regions of the nasal cavity. Neoplasms were associated with regions of respiratory metaplasia and were often covered with a low cuboidal, poorly ciliated epithelium. Tumor cells did not express characteristics of the olfactory mucosa, including olfactory marker protein (OMP, for neurons) and NMa (antibody recognizing cytochrome P450 [CYP] 2A3, found in Bowman's glands). Sites of plaque and tumor development coincided with regions of NMa immunoreactivity. These data suggest that local metabolism is important in alachlor-induced olfactory tumors and support the concept that metaplastic respiratory epithelial cells give rise to the observed neoplasms. (+info)The OMP-lacZ transgene mimics the unusual expression pattern of OR-Z6, a new odorant receptor gene on mouse chromosome 6: implication for locus-dependent gene expression. (6/76)
Reporter gene expression in the olfactory epithelium of H-lacZ6 transgenic mice mimics the cell-selective expression pattern known for some odorant receptor genes. The transgene construct in these mice consists of the lacZ coding region, driven by the proximal olfactory marker protein (OMP) gene promoter, and shows expression in a zonally confined subpopulation of olfactory neurons. To address mechanisms underlying the odorant receptor-like expression pattern of the lacZ construct, we analyzed the transgene-flanking region and identified OR-Z6, the first cloned odorant receptor gene that maps to mouse chromosome 6. OR-Z6 bears the highest sequence similarity (85%) to a human odorant receptor gene at the syntenic location on human chromosome 7. We analyzed the expression pattern of OR-Z6 in olfactory tissues of H-lacZ6 mice and show that it bears strong similarities to that mapped for beta-galactosidase. Expression of both genes in olfactory neurons is primarily restricted to the same medial subregion of the olfactory epithelium. Axons from both neuronal subpopulations project to the same ventromedial aspect of the anterior olfactory bulbs. Furthermore, colocalization analyses in H-lacZ6 mice demonstrate that OR-Z6-reactive glomeruli receive axonal input from lacZ-positive neurons as well. These results suggest that the expression of both genes is coordinated and that transgene expression in H-lacZ6 mice is regulated by locus-dependent mechanisms. (+info)Olfactory marker protein immunohistochemistry and the anterograde transport of horseradish peroxidase as indices of damage to the olfactory epithelium. (7/76)
The present study compared the relative effectiveness of wheatgerm agglutinin--horseradish peroxidase (WGA--HRP) and olfactory marker protein (OMP) in detecting the presence of intact olfactory axons in glomeruli of the main olfactory bulb (MOB) in the rat. The olfactory epithelium was damaged by i.p. injections of the toxin 3-methyl indole and, after 5 or 6 days, the olfactory sac was injected with a 1% WGA--HRP solution. No anterograde labeling was observed in the dorsal and ventromedial quadrants of the MOB in the WGA--HRP material. However, in the same cases OMP immunostaining was observed throughout the MOB. In other rats the rostral olfactory epithelium was aspirated unilaterally and after 3, 11 and 16 days the olfactory sacs were injected with WGA--HRP and rats were perfused 1 day later. In these cases WGA--HRP reaction product was absent in the dorsolateral quadrant of the MOB on the aspirated side in all animals, but OMP immunostaining could be detected in the 4 and 12 day survival animals but not in the 17 day survival rat. These findings indicate that anterograde transport of WGA--HRP accurately reflects the presence of intact axons en route to the MOB. In contrast, OMP immunostaining persists in axon terminals severed from their parent cell body for at least 12 days and is a less useful marker of intact olfactory axons in experiments using short survival times. (+info)Novel microglomerular structures in the olfactory bulb of mice. (8/76)
The murine olfactory system consists of two primary divisions: (1) a main olfactory system, in which olfactory sensory neurons (OSNs) located in the main olfactory epithelium (MOE) send their axons to glomeruli in the main olfactory bulb (MOB); and (2) an accessory olfactory system, in which OSNs located in the vomeronasal organ send their axons to glomeruli in the accessory olfactory bulb (AOB). In labeling studies using the lectin Ulex europaeus agglutinin (UEA), we discovered a novel subset of small neuropilar structures in the MOB that are distinct from other glomeruli both in the MOB and AOB. These "microglomeruli" are morphologically similar to MOB glomeruli in many respects: they receive innervation from processes present in the olfactory nerve layer and are isolated from other glomeruli by juxtaglomerular cells; in addition, the compartmental pattern of UEA labeling suggests the presence of UEA (-) processes within their neuropil. Microglomeruli contained processes that express the olfactory marker protein, a marker common to mature OSN axons. However, unlike other glomerular structures, the microglomeruli did not contain neural cell adhesion molecule-labeled processes. Within microglomeruli, UEA(+) processes interdigitated with MAP2(+) dendrites, some of which likely originate from interneurons, as indicated by glutamic acid decarboxylase labeling. Synaptophysin labeling in microglomeruli strongly suggested that synapses occur between UEA(+) processes and dendrites. Anterograde labeling of OSNs, by injection of rhodamine-dextran into one naris, demonstrated that UEA(+) processes in microglomeruli originated in the MOE. The unique morphology, protein expression, and location of microglomeruli have led us to hypothesize that they represent a novel class of glomerular structures in the murine olfactory system. (+info)The olfactory marker protein (OMP) is a specific type of protein that is primarily found in the olfactory sensory neurons of the nose. These neurons are responsible for detecting and transmitting information about odors to the brain. The OMP plays a crucial role in the function of these neurons, as it helps to maintain their structure and stability. It also contributes to the process of odor detection by helping to speed up the transmission of signals from the olfactory receptors to the brain.
The presence of OMP is often used as a marker for mature olfactory sensory neurons, as it is not typically found in other types of cells. Additionally, changes in the expression levels of OMP have been associated with various neurological conditions, such as Alzheimer's disease and Parkinson's disease, making it a potential target for diagnostic and therapeutic purposes.
The olfactory mucosa is a specialized mucous membrane that is located in the upper part of the nasal cavity, near the septum and the superior turbinate. It contains the olfactory receptor neurons, which are responsible for the sense of smell. These neurons have hair-like projections called cilia that are covered in a mucus layer, which helps to trap and identify odor molecules present in the air we breathe. The olfactory mucosa also contains supporting cells, blood vessels, and nerve fibers that help to maintain the health and function of the olfactory receptor neurons. Damage to the olfactory mucosa can result in a loss of smell or anosmia.
The olfactory bulb is the primary center for the sense of smell in the brain. It's a structure located in the frontal part of the brain, specifically in the anterior cranial fossa, and is connected to the nasal cavity through tiny holes called the cribriform plates. The olfactory bulb receives signals from olfactory receptors in the nose that detect different smells, processes this information, and then sends it to other areas of the brain for further interpretation and perception of smell.
Olfactory receptor neurons (ORNs) are specialized sensory nerve cells located in the olfactory epithelium, a patch of tissue inside the nasal cavity. These neurons are responsible for detecting and transmitting information about odors to the brain. Each ORN expresses only one type of olfactory receptor protein, which is specific to certain types of odor molecules. When an odor molecule binds to its corresponding receptor, it triggers a signal transduction pathway that generates an electrical impulse in the neuron. This impulse is then transmitted to the brain via the olfactory nerve, where it is processed and interpreted as a specific smell. ORNs are continuously replaced throughout an individual's lifetime due to their exposure to environmental toxins and other damaging agents.
Methyl n-Butyl Ketone, also known as Methyl Amyl Ketone or 2-Hexanone, is an organic compound with the molecular formula C6H12O. It is a colorless liquid with a pungent, fruity odor. It is used as a solvent in various industrial applications, including coatings, cleaning agents, and adhesives.
In a medical context, Methyl n-Butyl Ketone is primarily relevant as a potential occupational hazard. Exposure to this chemical can occur through inhalation, skin contact, or accidental ingestion during its use in industrial settings. Acute exposure to high levels of Methyl n-Butyl Ketone can lead to symptoms such as headache, dizziness, nausea, and respiratory irritation. Chronic exposure has been associated with neurological issues, including memory loss, confusion, and peripheral neuropathy.
It is essential for medical professionals to be aware of the potential health effects of Methyl n-Butyl Ketone, particularly in occupational settings, to ensure appropriate prevention measures are in place and to diagnose and manage potential exposures effectively.
The olfactory nerve, also known as the first cranial nerve (I), is a specialized sensory nerve that is responsible for the sense of smell. It consists of thin, delicate fibers called olfactory neurons that are located in the upper part of the nasal cavity. These neurons have hair-like structures called cilia that detect and transmit information about odors to the brain.
The olfactory nerve has two main parts: the peripheral process and the central process. The peripheral process extends from the olfactory neuron to the nasal cavity, where it picks up odor molecules. These molecules bind to receptors on the cilia, which triggers an electrical signal that travels along the nerve fiber to the brain.
The central process of the olfactory nerve extends from the olfactory bulb, a structure at the base of the brain, to several areas in the brain involved in smell and memory, including the amygdala, hippocampus, and thalamus. Damage to the olfactory nerve can result in a loss of smell (anosmia) or distorted smells (parosmia).
Nerve tissue proteins are specialized proteins found in the nervous system that provide structural and functional support to nerve cells, also known as neurons. These proteins include:
1. Neurofilaments: These are type IV intermediate filaments that provide structural support to neurons and help maintain their shape and size. They are composed of three subunits - NFL (light), NFM (medium), and NFH (heavy).
2. Neuronal Cytoskeletal Proteins: These include tubulins, actins, and spectrins that provide structural support to the neuronal cytoskeleton and help maintain its integrity.
3. Neurotransmitter Receptors: These are specialized proteins located on the postsynaptic membrane of neurons that bind neurotransmitters released by presynaptic neurons, triggering a response in the target cell.
4. Ion Channels: These are transmembrane proteins that regulate the flow of ions across the neuronal membrane and play a crucial role in generating and transmitting electrical signals in neurons.
5. Signaling Proteins: These include enzymes, receptors, and adaptor proteins that mediate intracellular signaling pathways involved in neuronal development, differentiation, survival, and death.
6. Adhesion Proteins: These are cell surface proteins that mediate cell-cell and cell-matrix interactions, playing a crucial role in the formation and maintenance of neural circuits.
7. Extracellular Matrix Proteins: These include proteoglycans, laminins, and collagens that provide structural support to nerve tissue and regulate neuronal migration, differentiation, and survival.
In the context of medicine, "odors" refer to smells or scents that are produced by certain medical conditions, substances, or bodily functions. These odors can sometimes provide clues about underlying health issues. For example, sweet-smelling urine could indicate diabetes, while foul-smelling breath might suggest a dental problem or gastrointestinal issue. However, it's important to note that while odors can sometimes be indicative of certain medical conditions, they are not always reliable diagnostic tools and should be considered in conjunction with other symptoms and medical tests.
The olfactory pathways refer to the neural connections and structures involved in the sense of smell. The process begins with odor molecules that are inhaled through the nostrils, where they bind to specialized receptor cells located in the upper part of the nasal cavity, known as the olfactory epithelium.
These receptor cells then transmit signals via the olfactory nerve (cranial nerve I) to the olfactory bulb, a structure at the base of the brain. Within the olfactory bulb, the signals are processed and relayed through several additional structures, including the olfactory tract, lateral olfactory striae, and the primary olfactory cortex (located within the piriform cortex).
From there, information about odors is further integrated with other sensory systems and cognitive functions in higher-order brain regions, such as the limbic system, thalamus, and hippocampus. This complex network of olfactory pathways allows us to perceive and recognize various scents and plays a role in emotional responses, memory formation, and feeding behaviors.