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PubMed1995

Taste and smell losses in HIV infected patients.

Human immunodeficiency virus (HIV-1) associated wasting is an increasingly common clinical manifestation of AIDS. The pathogenesis of wasting is multifactorial and includes reduced caloric intake as a major contributing mechanism. The perceptions of taste and smell play an important role in stimulating caloric intake and in optimizing nutrient absorption through cephalic phase reflexes. The purpose of this study was to evaluate the degree of losses in taste and smell function that occur in subjects infected with HIV. Taste and smell function was evaluated in 40 HIV infected individuals and 40 healthy control subjects matched for age, sex, race, smoking behavior, and number of years of education. Chemosensory tests administered to subjects included taste and smell detection thresholds, taste and smell memory tests, taste and smell discrimination tests, and taste and smell identification tasks. Significant differences were observed between experimental and control subjects in glutamic acid taste detection threshold (p < 0.001), quinine hydrochloride taste detection threshold (p < 0.001), menthol smell detection threshold (p < 0.001) and in the taste identification task (p = 0.006). Overall the results suggest abnormalities in the peripheral and central nervous systems, and subjective distortion of taste and smell. A significant correlation was not established between CDC classification of HIV infection and taste and smell function, although trends were observed suggesting worsening function with progression of HIV disease. These results document significant taste and smell losses in HIV infected subjects which may be of clinical significance in the development or progression of HIV associated wasting.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Olfactory bulbectomy disrupts the expression of cocaine-induced conditioned place preference.

The role of the olfactory sense in the expression of cocaine-induced conditioned place preference (CPP) was examined in adult male rats (n = 35) of the N/Nih strain. Consistent with the scientific literature, rats were observed to significantly (p < 0.05) increase (double) the seconds spent in their least-preferred chamber following cocaine-chamber pairings. Subsequently, groups of rats underwent one of three treatments: 1) olfactory bulbectomy (BULBX), 2) sham surgery (SHAM), or 3) sham surgery plus intranasal zinc sulfate perfusion (ZnSO4). Zinc sulfate was used to produce a temporary loss of olfaction. In a separate behavioral measure of olfactory acuity, both BULBX and ZnSO4-treated rats performed at an equally deficient level, in contrast to SHAM-treated rats that were not rendered anosmic. A second conditioned place preference test revealed that the ZnSO4-perfused and SHAM groups did not differ from their original postcocaine preference measurements. In contrast, the BULBX group spent significantly fewer seconds in the cocaine-paired chamber. After a 14-day interval, a third preference test revealed that SHAM and ZnSO4-treated rats displayed an equivalent preference for the cocaine-paired chamber (at 2.7 times above baseline). Interestingly, the seconds spent in the cocaine-paired chamber by BULBX rats did not differ from their baseline (e.g., precocaine exposure). These results suggest that bulbectomy disrupts the expression of cocaine-induced place preference. Interpretations of data from BULBX rats involving the production of an anhedonic condition and the relevance of olfactory bulbectomy as an animal model of anhedonic depression are discussed.

Animals↗
PubMed1996

Semantic-free scaling of odor quality.

The validity of the odor quality reports given by naive human subjects is often questionable. On the one hand, social conventions can influence the labeling of odorants, especially those that have putrid or uncommon odor qualities, and on the other, semantic differences exist for odor descriptors among individuals. We are interested in the individual differences in the quality reports elicited by two nominally putrid odorants, androstenone (AND) and pemenone (PEM). Here we sought to establish empirical support for the individual differences previously obtained in studies of their odor quality, using a nonverbal, semantic-free method of classification. Undergraduate volunteers sniffed a moderate concentration (390 microM) of PEM, rated its intensity, and provided a verbal odor descriptor. The subjects were then classified as PEM osmic (n = 42) if the quality report was putrid (rancid, urinous, sweaty), allosmic (n = 23), if the quality was nonputrid, and anosmic (n = 39) if no odor was detected. The subjects then sorted 15 odorants matched for intensity, five selected from each of three nominal odor quality types, into as many odor groups as they wished, as long as each group contained all of the compounds with similar odors. The number of times each odorant was paired with another was used as data for an independent multidimensional scaling with ALSCAL, for each class of subject. Three-dimensional solutions showed that this nonverbal, semantic-free scaling method produced odor classifications consistent with those found when each class of subject reported odor qualities from a defined list of quality descriptors. Cluster analysis of the MDS coordinates revealed that these solutions also retained the individual odor quality differences thought to be characteristic of osmic, allosmic and anosmic subjects.

Adult↗
PubMedDate not supplied

Visual loss and intoxication.

The Foster Kennedy Syndrome is very uncommon. The literature cited is often confusing. This paper presents a lucid definition of the syndrome that has contemporary diagnostic value and tenacious historical roots. We attempt to "sort-out" the true Foster Kennedy syndrome from its congeners and discuss the misnomers involved. An illustrative case is presented.

Adult↗
PubMed1975

Hypothalamic and pituitary function in hypogonadotropic hypogonadism.

Hypogonadotropic hypogonadism has been identified as a cause of partial or complete failure of puberty, may be familial and may have other associated abnormalities of hyposmia, intellectual retardation, perceptive deafness, color blindness, skeletal deformities, and gynecomastia. Pituitary function is usually normal with the primary defect believed to be hypothalamic. A twenty-year-old white male with a clinical diagnosis of hypogonadotropic hypogonadism and anosmia under-went complete endocrine evaluation with evaluation of the pituitary response to luteinizing hormone-releasing hormone. FSH (follicle-stimulating hormone) and LH (luteinizing hormone) release after luteinizing hormone-releasing hormone did occur, but the response was less than that seen in normal controls. Evaluation demonstrated that the pituitary-gonadal axis was intact with the hypothalamic-pituitary axis being defective. Therapy with the synthetic decapeptide (luteinizing hormone-releasing hormone) is correct theoretically and may be superior to therapy with exogenous gonadotropins.

Adult↗
PubMed1992

Olfactory loss and allergic rhinitis.

Olfactory loss is of importance for allergists to investigate in their patients, because if it is due to either allergic rhinitis or nonallergic rhinitis, it is potentially reversible. One should be sure to consider nasal polyposis and inflammation from chronic sinusitis, especially of the ethmoidal sinuses. Simple screening in the office can be achieved with an odor identification test of widely available substances as described above. Should there be no response to treatment or if the patient has a history of chronic sinusitis, recalcitrant nasal polyposis, or previous otolaryngologic procedures, further evaluation including rhinoscopy may be required. Recent olfactory loss in the absence of nasal symptoms and in the absence of abnormalities in the nasal cavity should suggest further investigation to look for a more central process. Morphologic investigation with electron microscopy of the olfactory epithelium and the superior nasal cavity is just beginning. The impact of inflammation in this area awaits investigation.

Adult↗
PubMed1991

The candidate gene for the X-linked Kallmann syndrome encodes a protein related to adhesion molecules.

Kallmann syndrome associates hypogonadotropic hypogonadism and anosmia and is probably due to a defect in the embryonic migration of olfactory and GnRH-synthesizing neurons. The Kallmann gene had been localized to Xp22.3. In this study 67 kb of genomic DNA, corresponding to a deletion interval containing at least part of the Kallmann gene, were sequenced. Two candidate exons, identified by multiparameter computer programs, were found in a cDNA encoding a protein of 679 amino acids. This candidate gene (ADMLX) is interrupted in its 3' coding region in the Kallmann patient, in which the proximal end of the KAL deletion interval was previously defined. A 5' end deletion was detected in another Kallmann patient. The predicted protein sequence shows homologies with the fibronectin type III repeat. ADMLX thus encodes a putative adhesion molecule, consistent with the defect of embryonic neuronal migration.

Amino Acid Sequence↗
PubMed1995

The genetic basis for specific anosmia to isovaleric acid in the mouse.

The detection and discrimination of odorants in mammals is thought to be mediated by a family of 100-1000 seven transmembrane domain receptor proteins, although none of these putative olfactory receptors have been shown to bind individual odorants with high affinity. We have used a genetic approach to identify the genomic regions responsible for the differential ability of two inbred mouse strains to detect a single odorant, isovaleric acid. Results obtained with a behavioral assay were consistent with a limited number of genes conferring the ability to detect isovaleric acid. One genetic location mapped to a 0.3 cM region between D4MIT37 and D4MIT156 on mouse chromosome 4. A second locus mapped to the distal end of mouse chromosome 6. The most likely cause of the behavior difference between the two strains of mice is the loss of the receptor protein or proteins responsible for recognizing isovaleric acid. High resolution genetic mapping provides a novel approach to the identification of genes critical for the detection of particular odorants.

Animals↗
PubMed1987

Loss of sense of smell in adult, hypothyroid mice.

Adult hypothyroid humans can lose their sense of smell. The present study was designed to investigate whether anosmia follows hypothyroidism in mice. If so, this would provide an animal model in which to study the mechanism for this effect. Adult mice were made hypothyroid with propylthiouracil (PTU) in their drinking water. Their sense of smell was tested before and after treatment by measuring the amount of time they spent sniffing food vs water odours, after a 24-h fast. Thyroid function was assessed histologically or by radioimmunoassay of blood serum for free thyroxine or free triiodothyronine. In Expt. 1 mice treated for 50 days with PTU were hypothyroid and anosmic. Control, euthyroid mice maintained their sense of smell, as did PTU-treated mice which also received daily thyroxine injections. PTU-induced anosmia was reversible: 50 days after removal of treatment previously anosmic mice were euthyroid and had regained their sense of smell (Expt. 3). It was possible that hypothyroidism induced non-specific effects which indirectly affected the olfactory function tests. However, short-term treatment with PTU caused severe hypothyroidism but no anosmia (Expt. 2). Additionally, non-specific effects of hypothyroidism were examined in open-field activity tests after short- and long-term hypothyroidism: euthyroid and hypothyroid animals were similarly active (Expts. 1 and 2). We conclude that chronic hypothyroidism produces anosmia in mice, as it does in humans. This anosmia is prevented by daily injections of thyroxine, and the sense of smell can recover to normal once thyroid function is restored.

Animals↗
PubMed1986

Chemoreception of taurocholate in anosmic and sham-operated cod, Gadus morhua.

This study investigated the role of the olfactory system in cod, Gadus morhua L., on the general activity level and the responses to the bile salt taurocholate. Ten cod were rendered anosmic by section of the olfactory tracts, while another 10 control fish were sham-operated. The cod were stimulated in a seawater olfactometer which permitted reproducible administration of diluted samples of taurocholate at 5 concentration levels. The activity scores for both groups of cod increased with increasing concentrations of taurocholate. The detection threshold in the sham-operated cod for taurocholate was 7 nM, while the anosmic cod detected the presence of taurocholate at 70 nM. Taurocholate induced orienting reaction and snapping, both in sham-operated and in anosmic cod, indicating convergence of olfactory and other chemosensory pathways to nerve centers mediating these kinds of behavior. The bottom food search was observed only in the control fish. The seawater blanks induced a lower total activity score in the anosmic than in the sham-operated cod, which suggests that the olfactory input augments the general activity level.

Acclimatization↗
PubMed1987

Absence of complete internasal-interocular transfer of habituation of exploratory behavior in rats.

Normal, blind, anosmic, and unilaterally blind and contralaterally anosmic albino rats were submitted to unilateral peripheral sensory (olfactory and/or visual) occlusion and observed in an initially unfamiliar arena. Next day, either the same sensory periphery (control subjects) or the contralateral one (experimental subjects) was occluded and a new observation in the arena was made. The duration of the exploratory behavior of control and experimental subjects, on each occasion, was compared. There was not a complete internasal-interocular transfer of long-term habituation of exploratory behavior, either when olfaction and vision were suppressed on opposite sides or when they were suppressed on the same side, but there was a complete internasal transfer of this habituation in blind animals and a complete interocular transfer of this habituation in anosmic animals. These results suggest that long-term habituation of the exploratory behavior elicited by one olfactory and one visual periphery activation and that of the exploratory behavior elicited by the other olfactory and the other visual periphery activation depend upon different representations of the stimulatory situation in the central nervous system. These representations would, however, have only a small number of elements which are not shared.

Animals↗
PubMed1980

Olfactory disturbances in Parkinsonism.

Disturbance of smell should be regarded as a common symptom of Parkinson's disease. It often presents as a precursor of the motor disability. The common underlying cause might be the deficiency of catecholamines in the brain of Parkinson patients, especially in the mesolimbic projection areas.

Discrimination Learning↗
PubMed1992

Evidence for genetic determination in human twins of olfactory thresholds for a standard odorant.

Olfactory thresholds for four odorants were determined in groups of monozygotic and dizygotic human twins. Odorants were presented in an ascending dilution series in odorless solvent, using a three-way forced choice method. For two of the tested odorants, 5 alpha-androst-16-en-3-one and isoamyl acetate, the thresholds showed a strong genetic component. This was demonstrated by respective values of 0.78 and 0.73 for the intraclass correlation difference, and of z = 3.69 and z = 2.71 in a within-pair difference analysis. The results for isoamyl acetate are novel, and suggest that genetic polymorphism in the affinity of odorant receptor proteins contributes to the (nearly normal) threshold distribution for this odorant.

Humans↗
PubMed1995

The effect of anosmia on MK-801-induced behaviour in mice.

Systemic administration of N-methyl-D-aspartate (NMDA) receptor antagonists induces a well defined behaviour in rodents characterized by, for example increased locomotion and ataxia. It is not clear in what brain region(s) NMDA antagonists induce this behaviour. We have studied the possible involvement of olfactory pathways by making adult mice anosmic via intranasal injection of zinc sulphate, a procedure that is known to destroy the olfactory epithelium. The NMDA antagonist MK-801 was given intraperitoneally (0.1-1.0 mg/kg) and the animals were scored for locomotion and ataxia 60-90 min later. Before MK-801 administration, olfactory-lesioned mice did not differ from non-lesioned controls with regard to locomotion or ataxia. MK-801 caused locomotor activation (> or = 0.2 mg/kg) and ataxia (> or = 0.5 mg/kg) in both groups. In general, olfactory-lesioned animals showed more locomotion and less ataxia after MK-801 administration than non-lesioned animals. Lesioned animals displayed 2.0- (P < 0.05) and 3.7-fold (P < 0.05) more extensive locomotor activation than non-lesioned animals after 0.5 and 1.0 mg/kg of MK-801, respectively. No difference in the degree of ataxia was seen between the two groups at 0.5 mg/kg, whereas non-lesioned animals showed a 2.1-fold higher degree of ataxia after 1.0 mg/kg of MK-801, indicating that the enhanced MK-801-induced locomotor activation in olfactory-lesioned mice was not simply due to less ataxia. These results suggest that olfactory input is involved in NMDA antagonist-induced behaviour.

Animals↗
PubMed1992

The effects of beta-endorphin infusions into the amygdala on visual and olfactory sensory processing during sexual behaviour in the male rat.

Sexually experienced male rats infused bilaterally into the amygdala with 60 pmol beta-endorphin show decreased rate of precopulatory investigation of the female and delayed intromission latency, but copulation is left unaltered. Such males are still able to discriminate between the odours of bedding from receptive and unreceptive females, demonstrating that beta-endorphin does not impair the ability to detect sexually relevant odours. Preventing visual cues emitted by females during proceptive behaviour (by treating them with haloperidol) delayed intromission latency but had no effect on preintromission investigation. Intra-amygdaloid beta-endorphin exacerbated the effects of this treatment on the intromission latency. Inducing anosmia in males (by applying zinc sulphate solution to the olfactory mucosa) decreased their anogenital investigation and delayed their intromission latency. These effects were not enhanced by intra-amygdaloid beta-endorphin. Allowing males to investigate and initiate the first intromission prior to intra-amygdaloid infusion had no effects on subsequent intromissions. However, if following an intromission with one female and an infusion of beta-endorphin, the male was presented with an unfamiliar female then the effects of intra-amygdaloid beta-endorphin on investigation and intromission returned. These results suggest that beta-endorphin in the amygdala interferes with the processing of female-specific olfactory information. Without this processed information, classification of the female as a sexual stimulus may be impeded and thus sexual arousal delayed.

Amygdala↗
PubMed1991

Effects of olfactory stimulation on the sleep time induced by pentobarbital administration in mice.

The effect on the pentobarbital sleep time by olfactory stimulation with various odorants was investigated using mice to appraise the physiological or psychological significance of olfactory information. The sleep time was determined as the time elapsed between intraperitoneal pentobarbital administration and the first time that the animal was able to spontaneously right itself. The sleep time was affected by inhalation of some odorants compared to pure air controls, but not by others. The sleep time was prolonged by terpinyl acetate and phenethyl alcohol, and was shortened by lemon oil and jasmin oil. However, neither potentiation nor attenuation of pentobarbital action by odorant inhalation was observed when using anosmic mice produced by intranasal zinc sulphate treatment. In conclusion, olfactory stimulation associated with odorant inhalation influences the pentobarbital sleep time, suggesting that olfactory information may have a more potent influence on the physiological and psychological status than has previously been thought.

Animals↗