OMP
Olfactory marker protein (Olfactory neuronal-specific protein)
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Knowledge of the vomeronasal neuroepithelium (VNNE) microanatomy is disproportionately based on rodents. To broaden our knowledge, we examined olfactory marker protein (OMP) expression in a sample of twenty-three non-human primates. The density of OMP ( ) vomeronasal sensory neurons (VSNs) in the VNNE was measured. Here we compared OMP ( ) VSN density in five species of Saguinus (a genus of New World monkey) of different ages to a comparative primate sample that included representatives of every superfamily in which a VNO is postnatally present. In Saguinus spp., the VNNE at birth is thin, usually comprising one or two nuclear rows. At all ages studied, few VNNE cells are OMP reactive as view in coronal sections. In the comparative sample, the OMP ( ) VSNs appear to be far more numerous in the spider monkey (another New World monkey) and the bushbaby (a distant relative). Other species (e.g., owl monkey) had a similar low density of OMP ( ) VSNs as in Saguinus. These results expand our earlier finding that few VSNs are OMP ( ) in Saguinus geoffroyi to other species of the genus. Our sample indicates that the number of OMP ( ) VSNs in primates varies from ubiquitous to few with New World monkeys varying the most. The scarcity of OMP ( ) cells in some primate VNOs reflects a lower number of terminally differentiated VSNs compared to a diverse range of mammals. If primates with relatively few OMP ( ) VSNs have a functional vomeronasal system, OMP is not critical for stimulus detection.
MeSH Terms
- Aging
- Animals
- Aotidae
- Atelinae
- Cell Count
- Epithelial Cells
- Epithelium
- Female
- Immunohistochemistry
- Lemur
- Male
- Olfactory Marker Protein
- Saguinus
- Saimiri
- Species Specificity
- Tarsiidae
- Vomeronasal Organ
To date, no study has been published on cell renewal in the olfactory epithelium of Chondrichthyes. Our work aimed at detecting proliferating cells (by Proliferating Cell Nuclear Antigen - PCNA immunohistochemistry) and apoptotic cells (by terminal uridine deoxynucleotidyl transferase nick end labeling method) in the olfactory epithelium of the shark Scyliorhinus canicula. PCNA immunoreactivity and mitotic figures were localized almost exclusively at the basal and apical thirds of the epithelial thickness. Double immunofluorescence for PCNA and OMP (a marker of mature olfactory neurons) showed that PCNA immunoreactivity is lacking in mature olfactory neurons, with the exception of crypt neurons. Crypt neurons, a cell type peculiar to fish, often showed PCNA immunoreactivity in the nucleus and may be involved in repair processes. The role of PCNA in mature crypt neurons requires further investigation to be clarified. Apoptosis was observed in sensory neurons and in basal cells. Our data highlight the presence of cell proliferation at different levels within the epithelium and the occurrence of apoptosis in both mature and proliferating cells.
MeSH Terms
- Aging
- Animals
- Apoptosis
- Cell Differentiation
- Cell Division
- Cell Proliferation
- Dogfish
- Female
- In Situ Nick-End Labeling
- Male
- Models, Animal
- Olfactory Mucosa
- Olfactory Receptor Neurons
Age-related changes in cell proliferation, neuronal differentiation, and cell death in mouse olfactory neuroepithelium were investigated. Mice at the age of 10 days through 16 months were given a single injection of bromodeoxyuridine (BrdU). The olfactory mucosae were fixed at 9 timepoints ranging from 2 hours to 3 months after the injection and examined using double immunostaining for BrdU and olfactory marker protein (OMP), and double staining with terminal deoxynucleotidyl transferase-mediated biotinylated dUTP nick end labeling (TUNEL) and immunostaining for OMP. The number of BrdU-labeled cells/mm epithelial length initially increased, peaked at 2-3 days after the BrdU injection, then declined at each age. The number of BrdU- and TUNEL-labeled neuronal cells both decreased with increasing age, suggesting that the rates of both cell proliferation and cell death in the olfactory neuroepithelium decrease with increasing age. Double-labeled cells for BrdU and OMP appeared at 7 days after injection in all age groups, suggesting that the time required for neuronal differentiation is broadly similar irrespective of age. In older age groups, smaller amounts of the newly produced cohort are integrated into the OMP-positive ORN population, and even once it is integrated it is eliminated from the population more rapidly compared to the younger age groups. Furthermore, TUNEL assay showed that the fraction of apoptotic cells distributed in the OMP-positive layer/total apoptotic cells decreased with age. This observation suggests that the turnover of mature ORNs is slower in the older neuroepithelium compared to the younger neuroepithelium.
MeSH Terms
- Aging
- Animals
- Antimetabolites
- Bromodeoxyuridine
- Cell Death
- Cell Differentiation
- Cell Proliferation
- Female
- Immunohistochemistry
- In Situ Nick-End Labeling
- Mice
- Olfactory Marker Protein
- Olfactory Mucosa
- Olfactory Receptor Neurons
The immunoreactivity and protein expression of olfactory marker protein (OMP) and tyrosine hydroxylase (TH) in the main olfactory bulb (MOB) of the dog during normal ageing was investigated. OMP immunolabelling was observed only in nerve bundles of the olfactory nerve (ONL) and glomerular layers (GL) and there was no OMP expression within cell bodies of any layer. TH immunolabelling was detected in all layers of the MOB except for the ONL. Most of the neurons expressing TH were distributed in the juxtaglomerular region and had a morphological appearance consistent with periglomerular, external tufted or superficial short axon cells. Dendrites of TH-immunoreactive neurons were closely apposed to OMP-immunoreactive nerve bundles within the glomeruli. There was no significant age-related loss of OMP and TH immunoreactivity and protein concentrations of these molecules were consistent in dogs of different ages. These results suggest that olfactory signal transduction to the GL via axons of olfactory receptor neurons remains unchanged during ageing in the dog.
MeSH Terms
- Aging
- Analysis of Variance
- Animals
- Blotting, Western
- Dogs
- Image Processing, Computer-Assisted
- Immunohistochemistry
- Male
- Microscopy, Confocal
- Neurons
- Olfactory Bulb
- Olfactory Marker Protein
- Olfactory Pathways
- Tyrosine 3-Monooxygenase
The present study examined interspecies, intersexual, and age-related changes in size of the vomeronasal neuroepithelium (VNNE) of two species of greater bushbabies (genus Otolemur, Infraorder Lorisiformes, Suborder Strepsirrhini). Tissue blocks containing the vomeronasal organs of nine O. crassicaudatus (8 adults, 1 neonate) and ten O. garnettii (9 adults, 1 neonate) were studied by means of serial paraffin sectioning and computer-based reconstruction of VNNE volume. In addition, the immunoreactivity of the VNNE to two neuronal markers, neuron-specific beta tubulin (BT) and olfactory marker protein (OMP) was compared between species, sexes, and ages. Results indicated that a clear VNNE is present at birth in both species, and OMP immunoreactivity was verified in O. garnettii at birth. Male and female adults of both species showed OMP-immunoreactive and BT-immunoreactive neurons in the VNNE. Immunohistochemical findings indicated that all males and the youngest females had the thickest VNNE, especially at the marginal junctions with the receptor-free epithelium. Results of a 2-way Analysis of Variance (ANOVA, species x sex) revealed no significant differences in VNNE length or volume between species, but O. crassicaudatus had significantly (p < 0.05) greater palatal length. Significant (p < 0.05) differences also were found between sexes in VNNE volume, but no significant differences in palatal length or VNNE length. The distribution of VNNE volume against age indicated that the sex differences were more pronounced in O. crassicaudatus than O. garnettii. For both species and sexes, distribution of VNNE volume against age suggested an age-related reduction in volume. These findings demonstrate postnatal plasticity in VNNE size in Otolemur that is reminiscent of that found for olfactory structures in some rodents. Bushbabies or other strepsirrhine primates may offer an opportunity for further understanding of behavioral correlates of VNNE postnatal plasticity, which may represent primitive functional characteristics of the order Primates.
MeSH Terms
- Aging
- Analysis of Variance
- Animals
- Female
- Fluorescent Antibody Technique
- Immunohistochemistry
- Male
- Nasal Mucosa
- Olfactory Marker Protein
- Olfactory Receptor Neurons
- Palate, Hard
- Sex Characteristics
- Species Specificity
- Strepsirhini
- Tubulin
- Vomeronasal Organ
Vomeronasal organ (VNO) morphology varies markedly across primate taxa. Old World monkeys display no postnatal VNO. Humans and at least some apes retain a vestigial VNO during postnatal life, whereas the strepsirrhines and New World Monkeys present a morphologically well-defined VNO that, in many species, is presumed to function as an olfactory organ. Available microanatomical and behavioral studies suggest that VNO function in these species does not precisely duplicate that described in other mammalian taxa. The questions of which species retain a functional VNO and what functions they serve require inquiry along diverse lines but, to be functional, the vomeronasal epithelium must be neuronal and olfactory. We used immunohistochemistry to establish these criteria in six primate species. We compared the expression of two neuronal markers, neuron-specific beta-tubulin (BT) and protein gene product 9.5, and olfactory marker protein (OMP), a marker of mature olfactory sensory neurons, in paraffin-embedded VNO sections from two strepsirrhine and four haplorhine species, all of which retain morphologically well-defined VNOs during postnatal life. The infant Eulemur mongoz, adult Otolemur crassicaudatus, neonatal Leontopithicus rosalia, and adult Callithrix jacchus express all three proteins in their well-defined vomeronasal neuroepithelia. The infant Tarsius syrichta showed some BT and OMP immunoreactivity. We establish that two strepsirrhine species and at least some New World haplorhines have mature sensory neurons in the VNO. In contrast, at all ages examined, Saguinus geoffroyi VNO expresses these markers in only a few cells.
MeSH Terms
- Aging
- Animals
- Animals, Newborn
- Biomarkers
- Female
- Immunohistochemistry
- Male
- Nerve Tissue Proteins
- Olfactory Marker Protein
- Olfactory Mucosa
- Olfactory Receptor Neurons
- Phylogeny
- Primates
- Species Specificity
- Tubulin
- Ubiquitin Thiolesterase
- Vomeronasal Organ
Vomeronasal neurons undergo continuous neurogenesis during development and after neuronal injury. We used immunocytochemical methods to compare different stages of the vomeronasal organ development to those of regeneration following vomeronasal nerve transection. At E15 and at 6 to 10 days after injury, nestin-positive cells were observed throughout the sensory epithelium. We did not find nestin immunoreactivity to be localized to the boundary region of the epithelium. The early appearance and wide distribution of nestin-positive cells suggests that they represent chemosensory precursor cells that develop and migrate vertically in the epithelium. Vomeronasal receptor cells degenerated 6 to 8 days after nerve transection, but axon terminals in the accessory olfactory bulb (AOB) continued to show the presence of the chemosensory specific marker (OMP) for up to ten days, a significant finding observed in this study. It is likely that the distance from the site of nerve transection may contribute to differences in the time course of anterograde and retrograde axon degradation. OMP-positive neurons were observed in the normal adult epithelium and to a much lesser extent 10-60 days after recovery from nerve transection. Axons from regenerated receptor cells did not reach the AOB during this time period. This failure to reestablish connections with target cells in the AOB could explain why OMP-positive cells were rarely observed among the regenerated cells in the vomeronasal epithelium.
MeSH Terms
- Aging
- Animals
- Chemoreceptor Cells
- Denervation
- Embryo, Mammalian
- Embryonic and Fetal Development
- Immunohistochemistry
- Intermediate Filament Proteins
- Nerve Degeneration
- Nerve Endings
- Nerve Regeneration
- Nerve Tissue Proteins
- Nestin
- Olfactory Bulb
- Olfactory Marker Protein
- Rats
- Rats, Sprague-Dawley
- Time Factors
- Vomeronasal Organ
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.
MeSH Terms
- Aging
- Animals
- Animals, Newborn
- Calbindin 2
- Immunohistochemistry
- Macaca
- Microscopy, Immunoelectron
- Nasal Mucosa
- Nerve Tissue Proteins
- Olfactory Marker Protein
- Olfactory Receptor Neurons
- S100 Calcium Binding Protein G
- Thiolester Hydrolases
- Ubiquitin Thiolesterase
In a line of transgenic mice (HpY-1), the pattern of expression of an olfactory marker protein (OMP)-lacZ fusion gene was analyzed in the cerebellum, where, in adult mice, OMP-lacZ was expressed primarily in Purkinje cells (PCs) of the posterior lobe. The transgene-expressing PCs were organized in parasagittal bands, with a boundary of expression roughly corresponding to the primary fissure that separates the cerebellum into anterior and posterior compartments. The regional expression of the lacZ gene was also analyzed during embryonic and postnatal development of the cerebellum. Within the cerebellum-isthmus region, transgene expression first was detected at embryonic day 13.5 (E13.5) in a cluster of postmitotic cells. By E14.5, lacZ was also expressed by a subpopulation of migrating PCs in the postisthmal and lateral cerebellar primordium, and, by E16.5, transgene-positive PCs formed caudally four sagittal bands symmetric to the medial embryonic fissure. The caudal pattern was retained in postnatal cerebella, where, by postnatal day 0 (P0), transgene-positive PCs in vermal lobules VIII and IX appeared to be organized in two prominent parasagittal compartments on either side of a negative midline band. In early postnatal animals, the transgene was expressed transiently in the anterior lobe vermis. Hence, from P5 onward, transgene expression appeared mostly restricted to the posterior lobe, where it followed a caudal-to-rostral gradient. In the paraflocculus, transgene-expressing PCs were confined to the rostrodorsal portion. The results indicate that the anterior and posterior cerebellar lobes are regulated by distinct ontogenetic programs, and PCs of functionally distinct cerebellar regions express the transgene differentially. Furthermore, the data suggest that ectopic expression of OMP-lacZ in the cerebellum is under the control of regulatory elements that provide positional information for the regional specification of PC subsets.
MeSH Terms
- Aging
- Animals
- Animals, Newborn
- Brain
- Cerebellum
- Gene Expression Regulation, Developmental
- Mice
- Mice, Transgenic
- Nerve Tissue Proteins
- Olfactory Marker Protein
- Purkinje Cells
- Recombinant Fusion Proteins
- beta-Galactosidase
Neurosecretory products immunologically related to either neuroparsin (NP) or ovary maturing parsin (OMP) of Locusta migratoria (Lom) were purified from the nervous corpora cardiaca of Schistocerca gregaria (Scg). The determination of both their molecular masses by mass spectrometry and their sequences by automated Edman degradation established that they are members of the NP and OMP families respectively. NP molecules of Schistocerca (Scg NPs) consisted of two major forms having about the same molecular masses as NPA and NPB of Locusta and 88% primary structure similarity. They had also the same antidiuretic activity. OMP molecules of Schistocerca (Scg OMPs) were composed in young adults of four isoforms: two long isoforms corresponding to Lom OMP, and differing by a tripeptide insertion (Pro-Ala-Ala) at position 21 and two short isoforms deprived of the 13-residue N-terminal peptide of Lom OMP and differing by the same tripeptide insertion. The PAA isoforms were observed in low amounts as compared to the other isoforms. In mature adults, only the two short isoforms were present. The complete sequence of PAA Scg OMP presents a large degree of sequence homology with Lom OMP (83%). The mixed Scg OMPs had the same biological effects as Lom OMPs. They induced precocious occurrence of both ecdysteroids and vitellogenin in the haemolymph and stimulated oöcyte growth.
MeSH Terms
- Aging
- Amino Acid Sequence
- Animals
- Chromatography, High Pressure Liquid
- Chromatography, Ion Exchange
- Female
- Grasshoppers
- Insect Hormones
- Insect Proteins
- Mass Spectrometry
- Molecular Sequence Data
- Nerve Tissue Proteins
- Nervous System
- Peptide Fragments
In infants, vaccines consisting of a carrier protein conjugated to the bacterial capsular polysaccharide (PRP) are far more protective against Hemophilus influenzae type b (Hib) disease than unconjugated PRP. To determine the tolerability and immunogenicity of Hib conjugate vaccines in the elderly, we vaccinated 30 volunteers, aged 69-84 years, with either PRP conjugated to an outer membrane protein complex (PRP-OMP), or PRP oligomers conjugated to CRM197, a nontoxic, mutant diphtheria toxin (HbOC). Prior to vaccination, 40% of subjects had serum anti-PRP antibody levels < 1.0 microgram ml-1. Four weeks following vaccination, all subjects had concentrations > 1.0 microgram ml-1, a level generally considered to be protective. The post-vaccination geometric mean concentrations were 35.5 and 50.1 micrograms ml-1 for the PRP-OMP and HbOC groups, respectively (0.05 < P < 0.10). Subjects in the HbOC group, but not the PRP-OMP group, showed, on average, ten fold increases in IgG antibody to diphtheria toxoid after conjugate vaccination. Side-effects of vaccination were mild except in one subject given HbOC, who developed extensive erythema and swelling of the injected arm.
MeSH Terms
- Aged
- Aged, 80 and over
- Aging
- Bacterial Outer Membrane Proteins
- Diphtheria Toxin
- Female
- Haemophilus Vaccines
- Humans
- Male
- Neisseria meningitidis
- Vaccines, Conjugate
We report characterization of several domains within the 5' flanking region of the olfactory marker protein (OMP) gene that may participate in regulating transcription of this and other olfactory neuron-specific genes. Analysis by electrophoretic mobility shift assay and DNase I footprinting identifies two regions that contain a novel sequence motif. Interactions between this motif and nuclear proteins were detected only with nuclear protein extracts derived from olfactory neuroepithelium, and this activity is more abundant in olfactory epithelium enriched in immature neurons. We have designated a factor(s) involved in this binding as Olf-1. The Olf-1-binding motif consensus sequence was defined as TCCCC(A/T)NGGAG. Studies with transgenic mice indicate that a 0.3-kb fragment of the OMP gene containing one Olf-1 motif is sufficient for olfactory tissue-specific expression of the reporter gene. Some of the other identified sequence motifs also interact specifically with olfactory nuclear protein extracts. We propose that Olf-1 is a novel, olfactory neuron-specific trans-acting factor involved in the cell-specific expression of OMP.
MeSH Terms
- Aging
- Animals
- Base Sequence
- Binding Sites
- Cell Nucleus
- DNA
- DNA-Binding Proteins
- Deoxyribonuclease I
- Female
- Male
- Mice
- Mice, Inbred Strains
- Mice, Transgenic
- Molecular Sequence Data
- Nerve Tissue Proteins
- Neurons
- Olfactory Bulb
- Olfactory Marker Protein
- Olfactory Mucosa
- Oligodeoxyribonucleotides
- Oligonucleotides, Antisense
- Organ Specificity
- Polymerase Chain Reaction
- Promoter Regions, Genetic
- Rats
- Transcription, Genetic
- beta-Galactosidase
Using immunohistochemical techniques, olfactory marker protein (OMP) was localized to the main (MOB) and accessory (AOB) olfactory bulbs of 30- and 45-day-old, and adult Brazilian opossums, Monodelphis domestica. Entire olfactory nerve and glomerular layers of the adult opossum MOB were darkly stained. In the adult AOB the rostral half of these two layers was stained more intensely than the caudal half, and both parts were less darkly stained than the MOB. This differential AOB staining was not present at 30 days of age, but was evident by postnatal day 45, although not as dramatic as in adults. This is the first report of differential OMP expression and may provide an approach to identifying the function of OMP.
MeSH Terms
- Aging
- Animals
- Immunohistochemistry
- Nerve Tissue Proteins
- Olfactory Bulb
- Olfactory Marker Protein
- Opossums
To evaluate the safety and immunogenicity of differing sequences of heterogeneous Haemophilus influenzae type b (Hib) conjugate vaccines, we randomly assigned 300 infants to one of six vaccination schedules. At 2, 4, and 6 months of age, subjects were given single or heterogeneous vaccines: Hib polysaccharide (PRP) conjugated to mutant diphtheria toxin (HbOC), PRP conjugated to outer-membrane protein of Neisseria meningitidis (PRP-OMP), or PRP conjugated to tetanus toxoid (PRP-T). No serious reactions were attributable to immunization with heterogeneous vaccines, and there were few significant differences in the rates of minor adverse reactions among groups. PRP-OMP was the only vaccine that induced an antibody response after the first dose, but significant booster responses were not seen after the second and third doses. Subjects given PRP-T vaccine responded well after two doses, but three doses of HbOC vaccine were needed for an equivalent antibody response. All the Hib vaccine schedules evaluated were immunogenic, and schedules initiated by PRP-OMP vaccine at 2 months of age, followed by two doses of either HbOC or PRP-T vaccine at 4 and 6 months of age, induced the highest antibody levels after each dose. Such schedules may be the best for protecting infants and children who are at greatest risk of having invasive Hib disease, such as American Indian children.
MeSH Terms
- Aging
- Analysis of Variance
- Antibodies, Bacterial
- Female
- Haemophilus Vaccines
- Haemophilus influenzae
- Humans
- Immunization Schedule
- Infant
- Injections, Intramuscular
- Male
- Safety
- Vaccines, Conjugate
Immunogenicity of one dose of Haemophilus influenzae type b (Hib) conjugate vaccine in infancy and its ability to induce immunologic memory was studied in infants immunized at 4 and 14 months with either PRP-OMP (Hib polysaccharide conjugated with Neisseria meningitidis group B outer membrane protein complex) or PRP-T (Hib polysaccharide-tetanus toxoid conjugate) and compared with three doses of the same vaccines at 4, 6, and 14 months. Each group received diphtheriatetanus-pertusis vaccine at 3, 4, and 5 months of age. At 7 months of age, both vaccines were immunogenic after one dose, even though higher antibody concentrations were achieved after two doses. A booster dose given at 14 months resulted in a high antibody concentration and a strongly IgG-dominated isotype distribution, speaking for a secondary-type response in all groups, including those who had received only one dose in infancy. Subsequent persistence of antibodies suggestive of full protection for up to 36 months was similar in all groups.
MeSH Terms
- Age Factors
- Aging
- Antibodies, Bacterial
- Bacterial Outer Membrane Proteins
- Haemophilus Vaccines
- Haemophilus influenzae
- Humans
- Immunoglobulin G
- Immunoglobulin M
- Immunologic Memory
- Infant
- Neisseria meningitidis
- Polysaccharides, Bacterial
- Tetanus Toxoid
- Vaccines, Conjugate
A 19,000-dalton acidic protein designated olfactory marker protein (OMP) is a cell-specific marker of mature olfactory chemosensory neurons. Intranasal irrigation of mouse olfactory epithelium with [35S]methionine labeled OMP to high specific activity. Turnover and transport characteristics of 35S-labeled OMP were compared to those of 35S-labeled global cytosol protein in groups of young, adult, and Triton-treated adult mice. The latter contained primarily large numbers of regenerating olfactory neurons. In olfactory epithelium of young and Triton-treated mice, the specific activity of OMP was three times that of global cytosol protein, whereas in adults the two measures were equal. In all three groups, however, the rate of degradation of OMP was roughly equal to that of cytosol protein (T1/2 = 5 to 6 days). By contrast, differences in T1/2 for OMP decline in the bulb of adult, young, and Triton-treated adult mice were highly significant (T1/2's of 9.3, 6.1, and 4 to 5 days, respectively; p = 0.001). The specific activity of [35S]methionine incorporated in OMP exceeded that of the free amino acid 5-fold, indicating minimal precursor reutilization during the course of our experiments. Turnover data indicate that increased isotope incorporation into OMP in the epithelium is matched by an accelerated rate of degradation in the bulb. This may be correlated with the physiological state or developmental age of the primary neurons since in young and Triton-treated adult mice, rapidly maturing "young" olfactory neurons represent a larger proportion of the total population than in adults. Thus, OMP behaves as a typical, relatively slowly transported soluble protein (v = 2 to 4 mm/day, slow component b).
MeSH Terms
- Aging
- Animals
- Epithelium
- Female
- Kinetics
- Methionine
- Mice
- Nerve Regeneration
- Nerve Tissue Proteins
- Neurons
- Octoxynol
- Olfactory Bulb
- Olfactory Marker Protein
- Olfactory Nerve
- Polyethylene Glycols
- Sulfur Radioisotopes
We are using the rat olfactory system to study developmental aspects of neurotransplantation (TX). Age-related TX maturation and subsequent establishment of connections are of special concern. Previous studies of deafferentation by olfactory bulb (OB) removal suggested "critical" periods of plasticity in the system. We present here preliminary attempts at relating age of host receiving TX to maturation of the TX and its connections. This investigation used hosts of postnatal age (PN) 13-14 days with fetal donors at Embryonic Day 15; the former having one OB ablated and receiving a fetal donor OB TX immediately placed in the vacated space. The fetal tissue was labeled previously in utero with tritiated thymidine. After 2 months a small coagulation lesion was placed in the OB TX and 2 days later the tissue was taken, serially sectioned, and processed for [3H] autoradiography, degeneration, and olfactory marker protein (OMP). Extensively 3H-labeled OB TXs with localized small lesions were studied. The cellular architecture of the TX is less well organized than in normals but substantial OMP reactivity occurs throughout. Degeneration occurs mainly near the lesion and little if any degeneration is seen beyond the 3H-labeled TX tissue. The results show that OB TX survive and develop in the PN 13-14 age group as they do in the younger animals and that primary olfactory neurons likewise reinnervate the TX but that PN 13-14 TX efferent projections are far more limited than those of younger hosts.
MeSH Terms
- Aging
- Animals
- Autoradiography
- Brain Tissue Transplantation
- Fetal Tissue Transplantation
- Olfactory Bulb
- Rats
- Rats, Inbred Strains
- Thymidine
- Tritium