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Dynamic spatiotemporal expression patterns of neurocan and phosphacan indicate diverse roles in the developing and adult mouse olfactory system.

The chondroitin sulfate proteoglycans neurocan and phosphacan are believed to modulate neurite outgrowth by binding to cell adhesion molecul … rostral pole of the telencephalon as well as by their arbors in glomeruli after they contacted the olfactory bulb. The role of neurocan was examined by growing olfactory neurons on an extracellular matrix substrate containing neurocan or on extracellular matrix in the presence of soluble neurocan. In both cases, neurocan strongly promoted neurite outgrowth. The …

Expression of the tight junction protein ZO-1 in the olfactory system: presence of ZO-1 on olfactory sensory neurons and glial cells.

The olfactory system is a unique part of the central nervous system since it retains neuronal turnover and regenerative capacities in adulth … sion of this tight junction component. ZO-1 expression has also been determined in cell cultures of olfactory bulbs. ZO-1 was present in the olfactory placode prior to formation of tight junctions. ZO-1 was localized in the developing and mature olfactory epithelium at heterotypic contacts between supporting cells and olfactory neurons as well as at homotypic co …

Amygdalar Gating of Early Sensory Processing through Interactions with Locus Coeruleus.

Fear- and stress-induced activity in the amygdala has been hypothesized to influence sensory brain regions through the influence of the amygdala on neuromodulatory centers. To directly examine this relationship, we used optical imaging to observe odor-evoked activity in populations of olfactory bulb inhibitory interneurons and of synaptic terminals of olfactory sensory neurons (the primary sensory neurons of the olfactory system, which provide the initial olfactory input to the brain) during pharmacological inactivation of amygdala and locus coeruleus (LC) in mice. Although the amygdala does n…

Carnosine in primary afferents of the olfactory system: an autoradiographic and biochemical study.

Previous in vivo studies have shown that beta-alanine is incorporated specifically into the dipeptide L-carnosine (beta-alanyl-L-histidine). In the present study, we administered beta-[3H]alanine to the nasal cavity of hamsters and used biochemical analyses to identify the radioactively labeled compounds in the olfactory epithelium and olfactory bulb and autoradiography to demonstrate the localization and transport of the label in the primary afferents of the olfactory system. The olfactory epithelium and lamina propria were labeled intensely 6 hr after intranasal beta-[3H]alanine administrati…

The HCN4 channel modulates external tufted cell burst firing.

Hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels are expressed widely in various brain regions and cardiac tissue. The HCN channel conductance, named as Ih (in neurons), plays a controlling role in neuronal excitability and rhythmic oscillatory activity in individual neurons and neuronal networks. Immunohistochemical studies in the literature show HCN channel isoforms are expressed in the olfactory bulb, but relative isoform expression levels are unknown. HCN channels are encoded by four genes (HCN1-4). The expression and function of those isoforms in the five types of…

Training with Odors Impacts Hippocampal Thickness in Patients with Mild Cognitive Impairment.

BACKGROUND: The olfactory system is affected early in Alzheimer's disease and olfactory loss can already be observed in patients with mild c … olfactory function, cognitive function, and morphology of medial temporal lobe (MTL) subregions and olfactory bulb in MCI patients. METHODS: A total of thirty-seven MCI patients were randomly assigned to the training group or a placebo group, which were performed twice a day for 4 months. Olfactory assessments, cognitive tests and magnetic resonance imaging wer …

Desipramine administered chronically inhibits lipopolysaccharide-stimulated production of IL-1β in the brain and plasma of rats.

Nowadays, it is assumed that therapeutic efficacy of antidepressants depends, at least partly, on their anti-inflammatory properties. The present study investigated for the first time the effect of 21-day oral administration of desipramine on the lipopolysaccharide (LPS)-stimulated IL-1β concentration in the olfactory bulb, hypothalamus, frontal cortex, hippocampus and plasma of rats, and on the LPS-induced IL-1β mRNA level in the olfactory bulb. Desipramine (15mg/kg/day) reduced significantly the LPS (250 μg/kg i.p.)-induced IL-1β concentration in the olfactory bulb, hypothalamus and in plasm…

Exploring of the Unpredicted Effects of Olfactory Network Injuries on Mammary Gland Degeneration: A Preliminary Experimental Study.

Purpose of the study: Hypofunctioning breasts are typically considered a dysfunction of higher brain centers that regulate hormonal feedback, and olfactory information has been proposed as a triggering factor for lactation in the maternal body. However, there are no substantive studies regarding whether olfaction disorders and/or loss of olfactory sense may result in breast gland atrophy by causing diminished olfactory stimulation. To fill this gap in the literature, we studied the histologic features of breast glands as a sample model in animals that had undergone an olfactory bulb lesion (OB…

Does intranasal application of zinc sulfate produce anosmia in the rat?

Transport of wheat germ agglutinin-horseradish peroxidase (WGA-HRP) from olfactory sensory neurons to the olfactory bulb as well as odor detection and discrimination were examined in rats in which each nasal epithelium had been irrigated with 0.1-0.5 ml 5% zinc sulfate. After treatment, rats showed few or no deficits in discriminating among odors and in detecting high (1%-0.01%) concentrations of ethyl acetate, but some had deficits in detecting lower concentrations of the odor. In most cases, HRP reaction product filled more than 30% of olfactory bulb glomeruli 2-4 days after treatment with Z…

CNPase expression in olfactory ensheathing cells.

A large body of work supports the proposal that transplantation of olfactory ensheathing cells (OECs) into nerve or spinal cord injuries can promote axonal regeneration and remyelination. Yet, some investigators have questioned whether the transplanted OECs associate with axons and form peripheral myelin, or if they recruit endogenous Schwann cells that form myelin. Olfactory bulbs from transgenic mice expressing the enhanced green fluorescent protein (eGFP) under the control of the 2-3-cyclic nucleotide 3-phosphodiesterase (CNPase) promoter were studied. CNPase is expressed in myelin-forming …

Specialized neuroglial arrangement may explain the capacity of vomeronasal axons to reinnervate central neurons.

The neurosensory cells of the primary olfactory and vomeronasal projections are in a state of continuous replacement throughout adult life. Since their axons form synaptic terminals with neurons in the olfactory and accessory olfactory bulbs, this system is an apparent exception to the rule that peripheral axons cannot grow into the central nervous system of adult mammals. Electron microscopy of sections (especially in a plane tangential to the surface of the accessory olfactory bulb) shows a unique glial arrangement. By virtue of their greater electron density and "secretory-type" organelle c…

Нейроинфламмация вызывает митральную дисфункцию клеток и обонятельное расстройство в множественной склерозовой модели.

Олокационная дисфункция является недооцененным симптомом множественного склероза (МС). Здесь мы изучили патогенные механизмы, лежащие в основе вызванной воспалением дисфункции обонятельной луковицы, используя животную модель MS, экспериментальный аутоиммунный энцефаломиелит (EAE). Результаты: Сокращенная обонятельная функция в EAE была связана с дегенерацией короткоаксоновых нейронов, незрелых нейронов, а также как митральных, так и тушёных клеток наряду с их синаптическим взаимодействием и аксонным репертуаром. Чтобы расчленить механизмы, лежащие в основе восприимчивости митральных клеток, гл

Совпадение в аннотации оригинала
BACKGROUND: Olfactory dysfunction is an underestimated symptom in multiple sclerosis (MS). Here, we examined the pathogenic mechanisms underlying inflammation-induced dysfunction of the olfactory bulb using the animal model of MS, experimental autoimmune encephalomyelitis (EAE). RESULTS: Reduced olfactory function in EAE was associated with the degeneration…

Extensive Connections of the Canine Olfactory Pathway Revealed by Tractography and Dissection.

The olfactory sense of the domestic dog is widely recognized as being highly sensitive with a diverse function; however, little is known about the structure of its olfactory system. This study examined a cohort of mixed-sex mesaticephalic canines and used diffusion tensor imaging (DTI), an MRI technique, to map connections from the olfactory bulb to other cortical regions of the brain. The results were validated using the Klingler dissection method. An extensive pathway composed of five white matter tracts connecting to the occipital lobe, cortical spinal tract, limbic system, piriform lobe, a…

Endoscopic endonasal resection of olfactory tract hamartoma for pediatric epilepsy.

BACKGROUND: Non-hypothalamic glioneural hamartomas are rare entities known to cause medically refractory epilepsy. Olfactory bulb hamartomas, in particular, are exceptionally rare. METHODS: We describe a case of an olfactory bulb hamartoma that was surgically resected at our institution. We also performed a literature review of all glioneural hamartomas and discuss the clinical presentation, diagnosis, and management of these lesions. RESULTS: Herein, we present the unusual case of a typically developing 17-year-old boy with a near life-long history of drug-resistant epilepsy, found to have …

Smelling of odorous sex hormone-like compounds causes sex-differentiated hypothalamic activations in humans.

The anatomical pathways for processing of odorous stimuli include the olfactory nerve projection to the olfactory bulb, the trigeminal nerve projection to somatosensory and insular cortex, and the projection from the accessory olfactory bulb to the hypothalamus. In the majority of tetrapods, the sex-specific effects of pheromones on reproductive behavior is mediated via the hypothalamic projection. However, the existence of this projection in humans has been regarded as improbable because humans lack a discernable accessory olfactory bulb. Here, we show that women smelling an androgen-like com…

Olfactory pathways in three patients with cryptococcal meningitis and acquired immune deficiency syndrome.

The olfactory mucosa, bulbs and tracts were examined for the presence of Cryptococcus neoformans in 3 patients with the acquired immune deficiency syndrome (AIDS) and cryptococcal meningitis. Two of them had antibodies against HIV-1 and one had positive serology for HIV-2. Cryptococci were seen in the subarachnoid space around olfactory tracts and bulbs and in the submucosal olfactory nerve fascicles. In one case, olfactory nerve fascicles from the lamina propria were also affected. Olfactory epithelium and respiratory mucosa were not involved. We suggest that Cryptococcus reached the olfactor

Identification of a cell surface glycoprotein family of olfactory receptor neurons with a monoclonal antibody.

A monoclonal antibody (Mab) has been developed which recognizes a family of cell surface glycoproteins found in high levels of rat olfactory receptor neurons. This Mab, designated 2B8, was produced by the fusion of X63-Ag8.653 myeloma cells and spleen cells of a mouse immunized with PC12 rat pheochromocytoma cells. Immunofluorescence analyses of cryostat sections of neonatal olfactory epithelium show prominent 2B8 binding to receptor neurons. Within the olfactory bulb only the glomerular and olfactory nerve layers show 2B8 binding. All other neural structures in the main olfactory bulb have ba…

Dehydroepiandrosterone regulates astroglia reaction to denervation of olfactory glomeruli.

Effects of dehydroepiandrosterone (DHEA) on glial reactions of the peripherally denervated olfactory bulb were studied in adult male rats. Denervation was achieved by destroying the olfactory mucosa with ZnSO(4) (0.17 M) irrigation of the nasal cavities. In one series of experiments, chronic DHEA treatment was applied (daily injections for 7 days, i.p., 10 mg/kg b.w. and 25 mg/kg b.w.); in the other series of experiments, animals received a single injection of DHEA (i.p., 10 mg/kg b.w., 25 mg/kg b.w. and 50 mg/kg b.w.) 2 h following ZnSO(4) treatment. To determine whether DHEA conversion to es…

Expression of SCG10 and stathmin proteins in the rat olfactory system during development and axonal regeneration.

The membrane-associated protein SCG10 is expressed specifically by neuronal cells. Recent experiments have suggested that it promotes neurite outgrowth by increasing microtubule dynamics in growth cones. SCG10 is related to the ubiquitous but neuron-enriched cytosolic protein stathmin. To better understand the role played by SCG10 and stathmin in vivo, we have analyzed the expression and localization of these proteins in both the olfactory epithelium and the olfactory bulb in developing and adult rats, as well as in adult bulbectomized rats. The olfactory epithelium is exceptional in that olfa…

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

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…