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At least 433 records · Page 24Linked to original sources
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↗
PubMed1991

Short nasal respiratory cilia and impaired mucociliary function.

A 48-year-old man was examined because of anosmia. He was otherwise healthy except for mild arterial hypertension. He had stopped smoking 20 years ago. Previously he had been exposed to sulfuric acid gases for 3 years in his work. Clinical examination revealed no findings to explain his anosmia. The patient was fertile, indicating normal sperm/cilia motility. Nasal mucociliary function was examined by radioactive tracer and found to be markedly and constantly impaired. Ciliary ultrastructure in cross-sections was normal. However, in longitudinal sections the length of the cilia varied from 0.6 microns to 3.9 microns. The mean length of the cilia from the cell membrane to the tip was 2.5 +/- 0.9 microns, in contrast to normal ciliary length of 5-7 microns. These findings represent a new structural defect among the various known ciliary abnormalities.

Cilia↗
PubMed1982

Immunocytochemical and ultrastructural correlates of the pineal inhibition of prolactin cell activity in blind-anosmic female rats.

The effects of the pineal gland on the light microscopic-immunocytochemical and ultrastructural appearance of pituitary mammotrophs were studied in female rats eight weeks after prepubertal blinding and olfactory bulbectomy. Blinding and anosmia resulted in a marked decrease in the size of the pars distalis concomitant with a reduction in the apparent number and size of PRL cells as compared with intact animals. Ultrastructurally, these cells appeared much less active than those of intact rats. The small and angular-shaped mammotrophs of blind-anosmic rats characteristically exhibited scant arrays of rough endoplasmic reticulum, small Golgi complexes with few immature secretory granules, few mature secretory granules and rare exocytosis patterns. Pinealectomy tended to reverse the effects of blinding and anosmia on pars distalis size and PRL cell size, apparent number and ultrastructure. In fact, the mammotrophs of blind-anosmic-pinealectomized rats were quite similar in ultrastructural appearance to those of intact rats. From these data we conclude that the pineal causes mammotroph hypotrophy and hypoplasia in blind-anosmic female rats.

Animals↗
PubMed1988

Examination and classification of human olfactory mucosa in patients with clinical olfactory disturbances.

To determine objectively the degree of olfactory disturbance, we biopsied the olfactory mucosa from patients who complained of anosmia. The olfactory disturbances in this study were caused by choanal atresia, chronic sinusitis, viral inflammation, and head trauma, as well as by congenital and idiopathic anosmia. The biopsy specimens were examined by light microscopy and the degree of mucosal degeneration present was classified according to five grades. The clinical courses of the patients studied paralleled the changes found in the olfactory mucosa.

Adolescent↗
PubMed2004

Kallmann syndrome: fibroblast growth factor signaling insufficiency?

Kallmann syndrome (KAL) is a developmental disease that combines hypogonadotropic hypogonadism and anosmia. Anosmia is related to the absence or hypoplasia of the olfactory bulbs. Hypogonadism is due to GnRH deficiency and is likely to result from the failed embryonic migration of GnRH-synthesizing neurons. These cells normally migrate from the olfactory epithelium to the forebrain along the olfactory nerve pathway. KAL is phenotypically and genetically heterogeneous. The gene responsible for the X-chromosome linked form of the disease (KAL1) has been identified in 1991. KAL1 encodes anosmin-1, an approximately 95-kDa glycoprotein of unknown function which is present locally in various extracellular matrices during the period of organogenesis. The recent finding that FGFR1 mutations are involved in an autosomal dominant form of Kallmann syndrome (KAL2), combined with the analysis of mutant mouse embryos that no longer express Fgfr1 in the telencephalon, suggests that the disease results from a deficiency in FGF signaling at the earliest stage of olfactory bulb morphogenesis. We propose that the role of anosmin-1 is to enhance FGF signaling and suggest that the gender difference in anosmin-1 dose (because KAL1 partially escapes X-inactivation) explains the higher prevalence of the disease in males.

Extracellular Matrix Proteins↗
PubMed2000

Antidepressants preferentially enhance habituation to novelty in the olfactory bulbectomized rat.

RATIONALE: The mechanisms whereby antidepressant drugs exert their therapeutic effects remain unknown. Responses to stressful stimuli are currently thought to contribute to the onset and course of affective disorders. It has been postulated that antidepressants might act by ameliorating response patterns to challenging life events, such as processes of reactivity and/or habituation. OBJECTIVE: Using the olfactory bulbectomy (OBX) rat model, this study examined the effects of various antidepressants on measures of reactivity and habituation in behavioral tests assessing responses to novel stimuli. METHODS: Sham-operated and OBX rats received 21 daily injections of fluoxetine (10 mg/kg), amitriptyline (10 mg/kg), desipramine (10 mg/kg), buspirone (3 mg/kg), or vehicle. Forty-eight hours after the last injection, animals were tested in the open field, elevated plus maze, and startle apparatus. For each test, time series data were collected and fit with exponential random effects models, in which estimated parameters assessed behavioral reactivity and habituation. RESULTS: Relative to sham controls, OBX rats displayed increased total locomotor activity in the open field and exhibited increased open arm behavior in the elevated plus maze. Through comparison with zinc sulfate-treated anosmic controls, these OBX-induced increases were attributed to both an augmentation of initial reactivity due to anosmia and an attenuation of the average rate of habituation. Chronic antidepressant treatment did not reduce the anosmia-related initial reactivity levels of OBX rats to that of sham controls. Rather, the antidepressants evoked their restorative effects by increasing the rate of habituation. CONCLUSIONS: These findings suggest that antidepressants restore normal responding by permitting more effective adaptation to novel stimuli.

Animals↗
PubMed2000

Multicenter investigation of 1,036 subjects using a standardized method for the assessment of olfactory function combining tests of odor identification, odor discrimination, and olfactory thresholds.

"Sniffin' Sticks" is a test of nasal chemosensory performance that is based on penlike odor-dispensing devices. It is comprised of three tests of olfactory function: tests for odor threshold, discrimination and identification. Previous work has already established its test-retest reliability and validity in comparison to established measures of olfactory sensitivity. The results of this test are presented as a composite TDI score--i.e., the sum of results obtained for threshold, discrimination and identification measures. The present multicenter investigation aimed at providing normative values in relation to different age groups. To this end, 966 patients were investigated in 11 centers. An additional study tried to establish values for the identification of anosmic patients, with 70 anosmics investigated in five specialized centers where the presence of anosmia was confirmed by means of olfactory evoked potentials. For healthy subjects, the TDI score at the 10th percentile was 24.5 in subjects younger than 15 years, 30.3 for ages from 16 to 35 years, 28.8 for ages from 36 to 55 years and 27.5 for subjects older than 55 years. While these data can be used to estimate individual olfactory abilities in relation to a subject's age, hyposmia was defined as the 10th percentile score of 16- to 35-year-old subjects. Our latter study revealed that none of 70 anosmics reached a TDI score higher than 15. This score of 15 is regarded as the cut-off value for functional anosmia. These results provide the basis for the routine clinical evaluation of patients with olfactory disorders using "Sniffin' Sticks."

Adolescent↗
PubMed1981

A quantitative study of the effects of early unilateral olfactory deprivation on the number and distribution of mitral and tufted cells and of glomeruli in the rat olfactory bulb.

Anatomic effects of early unilateral olfactory deprivation on the developing olfactory bulb were investigated in the albino rat. Unilateral anosmia was experimentally induced by neonatal cauterization of the left or right nare; regenerating the tissue permanently blocked the nostril. The anosmic olfactory bulb (ipsilateral to the blocked nare) and its contralateral counterpart, serving as the normal control, were compared for the following quantitative anatomic parameters: total number and distribution of mitral and tufted cells and olfactory glomeruli; average diameters of mitral cells and glomeruli; relative dimensions of the bulb and its layers. The effects on mitral cells and glomeruli were studied at the ages of 25 and 60 days and at 2 years; other studies were carried out in the 25-day-old animals only. In the normal mature bulb, the number of mitral cells, tufted cells and glomeruli was found to be about 70,000, 160,000 and 3000, respectively. It was found that the absence of early olfactory stimulation was invariably correlated with a significant and permanent loss of mitral cells, amounting to more than a quarter of the total number. This loss apparently occurred rapidly during the first 3 weeks, as it was already evident by day 25 and did not increase appreciably with prolongation of deprivation. Tufted cells were apparently even more susceptible, because their number decreased by about 45%. As evident from this distribution profiles, the loss of mitral and tufted cells occurred uniformly throughout the bulb. It is shown that these differences were due neither to inherent interbulbar differences, nor to a hyperplasia in the normal bulb. Early anosmia had no significant effects on the number or average diameter of the glomeruli. Morphometric studies revealed that the dimensions and thickness of layers (internal and external plexiform and granular) of the anosmic bulb were significantly reduced. It is suggested that early olfactory stimulation is necessary for survival of the developing mitral and tufted cells; thus the first 2-3 postnatal weeks, covering the final developmental stages of these cells, would constitute a vulnerable period in the development of the rat olfactory system.

Aging↗
PubMed1995

Involvement of the main but not the accessory olfactory system in maternal behavior of primiparous and multiparous ewes.

The respective roles of the main and accessory olfactory systems in the development of maternal behavior and selective suckling were investigated in parturient primiparous and multiparous ewes. Vomeronasal nerve section before parturition did not disturb either maternal behavior or maternal selectivity at suckling. By contrast, anosmia induced by zinc sulphate infusion had significant effects on the onset of maternal behavior in primiparous ewes. The onset of licking and of suckling were delayed and licking times and maternal bleats were reduced. Such disturbances were not observed in multiparous anosmic ewes, indicating that experience can compensate for the loss of olfactory information. On the other hand, anosmia prevented selective care regardless of maternal experience. Our results underline the importance of the main olfactory system for the development of adequate maternal behavior in sheep.

Animals↗
PubMed1994

Effects of intranasal ZnSO4 irrigation on olfactory and trigeminal cues.

Intranasal irrigation with ZnSO4 solutions is used for experimental induction of anosmia. It is, however, unknown whether the trigeminal nerve is affected by the treatment. One day after irrigation (concentrations investigated were between 0.05-1%) the ability of food finding, an olfactory cue, was decreased in a concentration-dependent manner. The trigeminal effect was investigated from a reflexively induced decrease in respiratory rate due to n-propanol exposure. No impairment occurred at 1% ZnSO4. Anosmia was also seen 2-3 h after an irrigation with solutions of 0.05-1% ZnSO4. At the same time, 0.2 and 1% solutions in themselves decreased the respiratory rate due to reflexes from the upper and lower respiratory tract. A conspicuous systemic effect can be ruled out as the Zn++ antidote, CaNa2EDTA, had no effect on the decrease. A direct activation of the trigeminal nerve due to a reaction with a thiol group may explain the effect from the upper airways.

1-Propanol↗
PubMed1994

Antidepressants suppress bulbectomy-induced augmentation of voluntary alcohol consumption in C57B1/6j but not in DBA/2j mice.

Bulbectomy has been previously shown to produce the specific antidepressant-sensitive syndrome in C57Bl/6j, but not DBA/2j mice. The present study examined the effect of the depression on voluntary alcohol consumption. Alcohol consumption and alcohol preference (% of alcohol solution in total liquid) in a free-choice, two-bottle situation was measured in C57BL/6j and DBA/2j mice after sham-operation, anosmia with 10% ZnSO4, or bulbectomy. Both anosmic and bulbectomized mice of both strains consumed more alcohol and showed stronger preference for alcohol than sham-operated mice. In DBA/2j mice both operations altered alcohol consumption of the whole population, and the effect of bulbectomy was stronger. In C57Bl/6j mice bulbectomy and, to a less degree, anosmia seemed to affect predominantly the low-drinking animals. Chronic treatment with antidepressants amitriptyline (20 mg/kg), trazodone (20 mg/kg), and imipramine (10 mg/kg), did not change alcohol consumption in sham-operated C57Bl/6j mice. In anosmic mice antidepressants decreased alcohol preference, but only amitryptyline also decreased alcohol consumption. All antidepressants decreased both alcohol consumption and preference in bulbectomized C57Bl/6j mice. In DBA/2j mice antidepressant treatment either increased, or did not alter alcohol consumption and preference in all groups, though the effects varied among individual antidepressants. The possible connection between the bulbectomy-induced behavioral syndrome and elevated ethanol consumption in C57Bl/6j mice is discussed.

Alcohol Drinking↗
PubMedDate not supplied

Skin conductance and subjective assessments associated with the odour of 5-alpha-androstan-3-one.

Two experiments are reported using the odours of 5-alpha-androstan-3-one (androstanone) and, a control odour, aurantiol. Various measures of skin conductance (SC) were recorded and analysed and subjects also rated the odours using analogue scales. The first experiment involved comparisons between subjects who perceive the androstanone odour as pleasant and subjects who perceive it as unpleasant. A number of differences were shown between the two groups and also between androstanone and aurantiol. The results are interpreted as demonstrating the influence of cognitive factors that are found between male and female responses and also between the responses of the 'pleasant' and 'unpleasant' groups. The second experiment examined the SC response of subjects who displayed specific anosmia to the odour of androstanone. The results suggest that the concept of specific anosmia requires modification.

Animals↗
PubMed1995

KAL, a gene mutated in Kallmann's syndrome, is expressed in the first trimester of human development.

Kallmann's syndrome (KS) is characterised by the association of anosmia and isolated hypogonadotrophic hypogonadism (IHH). Mutations of the KAL gene which is located at Xp22.3 cause X-linked KS (XKS). In this study we used the reverse transcriptase polymerase chain reaction and in situ hybridisation to examine the developmental expression of KAL in the first trimester of pregnancy, the earliest stage of human gestation examined thus far. At 45 days after fertilisation KAL mRNA was detected in the spinal cord, the mesonephros and metanephros but not in the brain. Later in gestation, at 11 weeks, the gene was expressed in the developing olfactory bulb, retina and kidney. This expression pattern correlates with the clinical findings in XKS since olfactory bulb dysgenesis with subsequent defective neural migration causes anosmia and IHH. Additionally, renal agenesis occurs in 40% of patients. Therefore this study provides strong evidence that KAL expression is required for the normal development of the olfactory bulb and kidney in the first trimester of human pregnancy.

Base Sequence↗
PubMed2006

Mutations in fibroblast growth factor receptor 1 cause Kallmann syndrome with a wide spectrum of reproductive phenotypes.

BACKGROUND: Kallmann's syndrome (KS) is a clinically and genetically heterogeneous disorder consisting of idiopathic hypogonadotropic hypogonadism (IHH) and anosmia. Mutations in KAL1 causing the X-linked form of KS have been identified in 10% of all KS patients and consistently result in a severe reproductive phenotype. KAL1 gene encodes for anosmin-1, a key protein involved in olfactory and GnRH neuronal migration through a putative interaction with FGFR1. Heterozygous mutations in the FGFR1 gene accompanied by a high frequency of cleft palate and other facial dysmorphisms were recently identified in 8% of a large KS cohort, yet the reproductive phenotype of KS patients harboring FGFR1 mutations has not been described. RESULTS: One hundred and fifty probands with KS (130 males and 20 females) were studied to determine the frequency and distribution of FGFR1 mutations and their detailed reproductive phenotypes. Fifteen heterozygous mutations in unrelated probands were identified. Twelve missense mutations (p.R78C, p.V102I, p.D224H, p.G237D, p.R254Q, p.V273M, p.E274G, p.Y339C, p.S346C, p.I538V, p.G703S and p.G703R) were distributed among the first, second and third immunoglobulin-like domains (D1-D3), as well as the tyrosine kinase domain (TKD). The mutations Y339C and S346C are located in exon 8B and code for the isoform FGFR1c. Additionally, two nonsense mutations (p.T585X and p.R622X) were documented in the TKD of the protein. A wide spectrum of reproductive function was observed among KS probands including: (1) a severe phenotype demonstrated by microphallus, cryptorchidism, no pubertal development, undetectable serum gonadotropins and low serum testosterone (T) and inhibin B; (2) partial pubertal development; (3) the fertile eunuch variant of IHH with normal testicular size and active spermatogenesis with a reversal of HH after T therapy. In addition, we found an even wider spectrum of reproductive function within pedigrees carrying an FGFR1 mutation ranging from IHH to delayed puberty to normal reproductive function (anosmia only or asymptomatic carriers). These observations strongly suggest a role for other genes that modify the phenotype of FGFR1 mutations. CONCLUSION: KS patients and family members carrying an FGFR1 mutation present a broad spectrum of pubertal development in contrast to the almost uniform severe clinical phenotype described in KS subjects with a KAL1 mutation. Additionally, this report implicates the isoform FGFR1c in the pathogenesis of KS.

Adolescent↗
PubMed2004

Olfactory loss as a result of toxic exposure.

Olfactory loss can occur through accidental exposure, poor industrial hygiene, or exposure to low levels of toxins in the ambient air over long periods. This loss can lead to transient olfactory disorders, irreversible anosmia, temporary olfactory fatigue, or industrial anosmia. Inevitably, a practicing otolaryngologist will encounter a patient with complaints of decreased smell and taste that initially may be difficult to diagnose and treat. Much of the challenge in evaluating a patient with disturbances of olfaction is in obtaining adequate quantitative measurements of sensory dysfunction and identifying a source for the olfactory loss. Although there is no particular test for environmental toxins as a source of olfactory loss, an accurate cause can be determined by obtaining a careful, detailed history. A significant exposure history and lack of more common causes of olfactory loss strengthens an argument for environmental toxins as an etiology. Unfortunately, no available treatments can reverse permanent damage caused by toxic exposure, but removal from the source of toxins may allow for repair of the olfactory system and return of normal function, especially in acute exposures. Despite the increasing number of studies investigating toxic exposure on olfactory function, these effects are understood poorly. With continued study of human exposure to these substances and the use of animal models, the mechanisms by which damage occurs will be understood better and new approaches for diagnosis and treatment will be developed. Furthermore, with increasing regulations of occupational environments and stricter policies on industrial air pollution, olfactory dysfunction secondary to toxicity should become less prevalent.

Drug-Related Side Effects and Adverse Reactions↗
PubMedDate not supplied

[Hematoma of the olfactory bulbs following craneoencephalic trauma].

The ability to smell is commonly altered by head injuries. However, the nature, prevalence, prognosis and etiology of such alterations are poorly understood. Patients complaining of head-trauma and a related olfactory dysfunction typically have anosmia and rarely regain normal olfactory ability. Parosmia prevalences decreases over time in such patients, and damage to olfaction-related brain structures can be observed in most such patients using an appropriate MRI protocol. In this article, we review the recent knowledge about postraumatic anosmia.

Adult↗
PubMed1995

Pregnancy in women with Kallmann's syndrome.

OBJECTIVE: To induce of ovulation and pregnancy in women with Kallmann's syndrome. DESIGN: Retrospective study. PATIENTS: Three women with hypogonadotropic hypogonadism and anosmia with a desire for pregnancy. INTERVENTIONS: Investigation of hypothalamic-pituitary-ovarian function and induction of ovulation by pulsatile GnRH or intramuscular human pituitary gonadotropins (hPG) or hMG with hCG. MAIN OUTCOME MEASURES: Successful induction of ovulation as measured by serum P levels and successful pregnancy. RESULTS: Ovulation was induced successfully in all three patients on more than one occasion and nine pregnancies occurred. Gonadotropin-releasing hormone was given IV by an electronically timed syringe driver. A total of 12 pulsatile GnRH cycles resulted in two pregnancies, 6 of these cycles being in one patient who did not ovulate or conceive with this therapy. Ovulation occurred in 10 of 16 hMG or hPG cycles, with conception in 7 of these. Gonadotropin usage was higher in these women compared with women with hypogonadotropic hypogonadism without anosmia (2,850 compared with 2,100 IU per treatment cycle), and the follicular phase was longer. CONCLUSIONS: All three women conceived and had children after induction of ovulation. The success rate of these therapies in Kallmann's syndrome appears to be high in spite of very few reports in the literature.

Adolescent↗
PubMedDate not supplied

The influence of olfaction on potentiation and inhibition of ultrasonic vocalization of rat pups.

Twelve-day-old isolated rat pups reduce their rates of ultrasonic vocalization (USV) when an anesthetized adult is placed into the test cage, whether the adult is their dam or an unfamiliar male. USV rates remain very low even after removal of the male (inhibition). However, after removal of the dam, pups greatly increase their rates of USV over their first isolation period (potentiation). USV potentiation can be induced by either an awake, normally behaving dam or by one that is anesthetized. To test the role of olfaction in inhibition and potentiation, PND12 pups were rendered anosmic via intranasal infusion of 5% zinc sulphate (ZnSO4). Control pups were infused with normal saline. After overnight separation from the dam, the USV and other behaviors of pups were recorded during a 6-min test. Each pup was tested during an initial isolation period and a final isolation period. In the first experiment, an anesthetized adult (dam or unfamiliar male) or no companion was placed in contact with the pup during the middle minute. Anosmia prevented both potentiation and inhibition of USV by passive adult contact. Thus, it seems likely that pups use olfactory discrimination as the basis for these two highly differentiated vocal responses to social stimuli. Results from two additional experiments demonstrate that anosmia does not prevent potentiation when the adult dam is active and interacting with the pup on either postnatal day 12 or 8.

Animals↗