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At least 199 records · Page 11Linked to original sources
PubMed1975

[Significance of olfaction in the feeding behavior of toads (Amphibia, Anura, Bufonidae): studies with the natterjack (Bufo calamita Laur.)].

The influence of olfactory and visual prey stimuli on the feeding behaviour of toads was studied as well as their response to lasting olfactory cues. A further aim was to find simple methods for testing olfactory responsiveness in anurans. Subjects were 8 adult specimens of the European species Bufo calamita (natterjack) kept in captivity one year at least. The results point to the rôle of olfaction in these animals.

Animals↗
PubMed2006

[The advance of research in electro-physiology and chip techniques for olfaction and gustation].

This paper introduces the new research achievement and progress of electro-physiology in olfaction and gustation. Classical implements such as patch-clamp or glass pipette are not appropriate in the dynamic detection of cellular signal transportation. In view of this, we have analyzed the feasibilities and challenges of olfactory or gustatory cell-based biosensors such as field effect transistor (FET) and light addressable potentiometric sensor (LAPS). Finally we present the research work carried our in out lab and a future prospective on the development in this field.

Biosensing Techniques↗
PubMed1990

Current concepts in olfaction.

Because of the location of the olfactory epithelium and bulb, the processes involved in olfaction have been difficult to evaluate. However, the recent application of comprehensive nasal endoscopy, reproducible olfactory testing, and molecular biologic techniques to the study of the transduction of olfactory information has elucidated some of the events in odorant perception.

Chronic Disease↗
PubMed1989

The influence of olfaction on exploratory behaviour in the paradise fish (Macropodus opercularis L.).

We studied the role of olfaction on the exploratory behaviour of the paradise fish. Intact animals showed habituation of exploratory behaviour toward a heterospecific fish after five consecutive encounters. Fish with olfactory nerves destroyed spent significantly longer time with exploration compared to the control even at the fifth encounter. We suggest that olfactory inputs have a strong influence on exploratory behaviour.

Animals↗
PubMed1993

Early events in olfaction: diversity and spatial patterns of odorant receptors.

In the past few years, a major advance was made in understanding early events in olfaction. In particular, a molecular basis for the sense of smell has emerged. I will focus on the most recent data obtained on an extremely large subfamily of putative odorant receptors. These results may explain how the olfactory system can recognize and distinguish thousands of odoriferous molecules and how the spatial coding of odor molecules could be generated in the olfactory epithelium and subsequently transmitted to the olfactory bulb. The putative odor receptors are a subfamily of seven-transmembrane-domain G protein-coupled receptors; although their functions have not yet been definitively proven, they may act as odor receptors. This new receptor gene family has the following characteristics: 1) It is a multigene family of phylogenetically related sequences consisting of approximately 100 members in fish and up to approximately 1000 members in rodents. 2) Members of this family are expressed in the olfactory epithelium (olfactory receptors). Related genes are expressed in the gustatory epithelium of the tongue (gustatory receptors), and in sperm cells (germ-cell receptors). 3) Genes for the olfactory receptor family have been isolated from several species including fish, rat, mouse, human and chick. 4) Olfactory receptor protein seems to be localized on the ciliary surface of olfactory neurons. 5) On the basis of a reconstitution experiment, olfactory receptors exhibit broad ligand specificity. 6) A single receptor is expressed in only 0.1%-2% of the entire olfactory neuron population.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

The olfactory bulb in Alzheimer disease: a morphologic study of neuron loss, tangles, and senile plaques in relation to olfaction.

Complete pairs of olfactory bulbs of six Alzheimer disease (AD) patients and of six age- and sex-matched controls were morphologically investigated using a random systematic sampling procedure. The total number of cells and the number of mitral cells were the same for controls and patients, but the volume of the bulb and the number of neurons in the anterior olfactory nucleus (AON) were decreased in AD patients. The loss of AON neurons was limited to the younger AD patients and was very severe (75%). Neurofibrillary tangles (NFT) and senile plaques (SP) were found in controls, but they were more frequent in AD, especially in the younger cases. A new finding was the occurrence of very large numbers of so-called diffuse or "very primitive plaques" with the methenamine-silver stain (MS-SP). NFT and SP were limited to the AON but MS-SP also occurred in other parts of the bulb. The data are discussed in relation to olfaction, and it was concluded that odor identification is processed in central rather than in peripheral olfactory structures.

Aged↗
PubMed1996

Olfaction and the homing ability of pigeons in the southeastern United States.

The importance of atmospheric odors for homing pigeon navigation was tested using birds from a loft located in Savannah, GA, in the southeastern United States. When released from a familiar training site, control pigeons and pigeons given intranasal injections of zinc sulfate to produce anosmia both displayed good homeward orientation and homed quickly. When released from three unfamiliar release sites, in contrast, control birds tended to orient southeast, while zinc sulfate-treated birds were more likely to fly northwest. More importantly, while the majority of control pigeons returned to the home loft, few of the zinc sulfate-treated birds returned. The good performance of both groups from the familiar site indicates that zinc sulfate treatment does not impair the general motor ability or motivation of homing pigeons. Therefore, the observed impairment in homing success of the zinc sulfate-treated pigeons from the unfamiliar locations presumably reflects an impaired ability to use atmospheric odors to navigate home. As such, the data support the hypothesis that successful homing pigeon navigation is based on the perception of atmospheric odors and that olfactory navigation is the primary mechanism used by pigeons over a broad range of geographic areas to approximate their relative position with respect to home from unfamiliar locations.

Animals↗
PubMed2001

Loss of olfaction in de novo and treated Parkinson's disease: possible implications for early diagnosis.

Olfactory dysfunction is a common finding in patients with Parkinson's disease (PD). As most studies reported on odor identification in more advanced and treated PD, we administered an odor detection, discrimination, and identification test to a heterogeneous, partly de novo, group of patients. Forty-one non-demented PD patients, 24 of whom had untreated early PD, and 18 healthy controls, were examined. Odor identification and discrimination data were corrected for odor detection scores. PD patients scored significantly lower on all olfactory tests. Interestingly, the subgroup of de novo patients with early PD also showed significant olfactory disturbances compared with healthy subjects. Within the PD group, using multiple regression analysis, we found a significant, negative correlation between odor discrimination measures and disease The present study is the first to describe decreased performance of PD patients on odor discrimination, in addition to the already well-established deficits in odor detection and identification. Furthermore, odor discrimination measures were related to disease severity, possibly indicating that at least some aspects of olfactory dysfunction in PD may be secondary to ongoing degenerative processes in PD. As significant olfactory impairments were found in early, de novo PD, olfactory tests may be useful in the early diagnosis of PD.

Adult↗
PubMed2004

Olfaction and the homing ability of pigeons raised in a tropical area in Brazil.

Several workers have investigated the effect of anosmia on pigeon navigation in different geographical locations because it has been suggested that homing behavior is based on different cues, such as olfactory cues, the Earth's magnetic field or infrasound, and that in the absence of one cue another would be used. In this situation, no cue is universally indispensable, including olfactory ones. In order to extend such observations to a novel biome, we observed the behaviour of 192 young inexperienced birds raised in southeastern Brazil, a tropical area where olfactory tests had never been run before. The birds were released from eight symmetrically distributed sites 17 to 44 km from the loft. Half of these birds (experimentals) had been made temporarily anosmic by washing their olfactory mucosae with 4% solution of ZnSO4 the day before release, while controls were treated with Ringer solution. The results of release tests showed that anosmia totally impaired the navigational performance of experimental birds, which were unable to home from sites at relatively short distances from home (34-44 km) and whose pooled initial bearings produced a (negative) homeward component not significantly different from 0. Homing performance of controls was significantly better, and their pooled vanishing bearings had a significant homeward component, in spite of much scatter in individual releases. We conclude that pigeon homing in the study area depends on olfactory information, even though local environmental conditions in the interior of the State of Sao Paulo, as in several other parts of the world, do not appear to be as favorable as Italy for the development of efficient olfactory navigation.

Animals↗
PubMed2003

Olfaction in neurodegenerative disorder.

There has been an increase of interest in olfactory dysfunction since it was realised that anosmia was a common feature of idiopathic Parkinson's disease (PD) and Alzheimer-type dementia (AD). It is an intriguing possibility that the first sign of a disorder hitherto regarded as one of movement or cognition may be that of disturbed smell sense. In this review of PD, parkinsonian syndromes, essential tremor, AD, motor neurone disease (MND) and Huntington's chorea (HC) the following observations are made: 1). olfactory dysfunction is frequent and often severe in PD and AD; 2). normal smell identification in PD is rare and should prompt review of diagnosis unless the patient is female with tremor-dominant disease; 3). anosmia in suspected progressive supranuclear palsy and corticobasal degeneration is atypical and should likewise provoke diagnostic review; 4). hyposmia is an early feature of PD and AD and may precede motor and cognitive signs respectively; 5). subjects with anosmia and one ApoE-4 allele have an approximate 5-fold increased risk of later AD; 6). impaired smell sense is seen in some patients at 50% risk of parkinsonism; 7). smell testing in HC and MND where abnormality may be found, is not likely to be of clinical value; and 8). biopsy of olfactory nasal neurons shows non-specific changes in PD and AD and at present will not aid diagnosis.

Apolipoprotein E4↗
PubMed2003

Olfaction in essential tremor patients with and without isolated rest tremor.

An olfactory deficit is present in patients with essential tremor (ET), but it is often milder than that in patients with Parkinson's disease (PD). In both, the deficit occurs early in the disease. Isolated rest tremor without other signs of parkinsonism can occur in patients with ET. If the rest tremor in these patients represents a manifestation of ET rather than early PD, we hypothesized that their University of Pennsylvania Smell Identification Test (UPSIT) scores would be similar to those of ET patients without rest tremor. The mean UPSIT score in 13 ET patients with isolated rest tremor did not differ from that of 58 ET patients without rest tremor (29.3 +/- 4.3 vs. 29.4 +/- 6.4; P = 0.69). Several ET patients with rest tremor had UPSIT scores that fell outside of the range that is seen in 95% of patients with PD. These data raise the possibility that some ET patients with isolated rest tremor may not have early PD and that the pathological process that is responsible for their ET is also involving the basal ganglia.

Aged↗
PubMed1993

The significance of olfaction and social cues in milt availability, sexual hormone status, and spawning behavior of male rainbow trout (Oncorhynchus mykiss).

Male rainbow trout orientate to a "releaser" pheromone emitted by an ovulated female. This chemical signal is not necessary for the completion of spawning behavior: anosmic males spawned as readily as intact males when paired with ovulated females. The amount of "strippable" milt and plasma concentrations of testosterone (T) and 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta-P) were greater in males paired for 3 hr with ovulated females than in isolated males, or males placed with nonvitellogenic adult females or in all male groups. Milt and plasma T, 17,20 beta-P, and 11-ketotestosterone (11-KT) were reduced in anosmic males paired with ovulated females, indicating the existence of a priming pheromone. Milt, T, 11-KT, and 17,20 beta-P increased in intact males within 4 hr after injection of salmon gonadotrophin-releasing hormone analogue, lyophilized salmon pituitary extract, or homogenized fresh rainbow trout pituitary material. The results indicate that the priming pheromone acts through the hypothalamus-pituitary-gonad axis.

Animals↗
PubMed2004

Olfaction and anosmia in rhinosinusitis.

Olfactory disorders can cause serious consequences from the inability to detect many olfactory warning signals (eg, smoke, spoiled food, and gas leaks) and can significantly impact nutritional status, eating satisfaction, and many other issues related to quality of life. More than 200,000 people a year seek treatment for impaired olfactory ability, and available evidence suggests this figure is a significant underestimate of those affected. Rhinitis and rhinosinusitis are the primary etiologies for olfactory loss or distortion among patients presenting to chemosensory clinics, and they are among the most common chronic medical conditions in the United States, affecting an estimated 33 million people. Both allergic and nonallergic rhinitis/rhinosinusitis can result in diminished, distorted, or absent olfactory ability. Current therapies are only partially or transiently effective in reversing olfactory loss. The underlying mechanisms by which rhinitis/rhinosinusitis impact olfactory ability are likely to be multifactorial and might include altered air flow and odor deposition, changes in mucus composition, and effects of inflammatory mediators on receptor cell differentiation, maturation, or function.

Humans↗