Abstract: Impaired olfaction occurs in patients with idiopathic Parkinson's disease (PD), and Lewy bodies have been found in the olfactory bulb and tract. We now confirm the latter finding and show that this presence of Lewy bodies is associated with significant neuronal loss. A quantitative study of the anterior olfactory nucleus (AON) was performed in tissue obtained postmortem from seven patients with PD and seven age-matched controls. Neuronal loss was seen in the PD bulb and tracts (p < 0.01), and a strong correlation of neuronal loss with disease duration was detected (R = -0.87). The presence of Lewy bodies was confirmed with immunocytochemical staining for ubiquitin in all the PD cases.

Abstract: Odours play a very important role in the life of insects belonging to the order Lepidoptera. In the present paper, a review is given of the current knowledge of morphology, development and function of the olfactory system in larval and adult moths and butterflies. Research regarding both the antennal and accessory olfactory pathways, as well as both the pheromone and the host odour detecting systems, is reviewed.

Abstract: Introduction - Olfaction is markedly impaired in patients with idiopathic Parkinson's disease (IPD). This deficit contrasts with reports of preserved or only mildly reduced olfaction in patients with atypical parkinsonism. However, the sensitivity and specificity of olfactory function testing in the differential diagnosis of parkinsonian syndromes has not been studied. In addition, olfactory function in patients with corticobasal degeneration (CBD) is unknown. Material and methods - Using the University of Pennsylvania Smell Identification Test (UPSIT) with a test score ranging from 0 to 40 we studied olfactory function in patients with IPD as well as other parkinsonian syndromes including CBD and progressive supranuclear palsy (PSP). Results - UPSIT scores in 118 patients with IPD, 29 with MSA, 15 with PSP, and 7 patients with CBD, as well. as in 123 healthy control subjects revealed a marked impairment in the IPD group in contrast to mild impairment in MSA patients and normal olfaction in PSP and CBD patients. An UPSIT score of 25/40 was associated with a sensitivity of 77% and a specificity of 85% in differentiating IPD from atypical parkinsonism. Conclusions - These results indicate that olfactory function is differentially impaired or preserved in distinct parkinsonian syndromes and that it might also have some value as a diagnostic pointer. Thus, preserved or mildly impaired olfactory function in a parkinsonian patient is more likely to be related to atypical parkinsonism such as MSA, PSP or CBD, whereas markedly reduced olfaction is more suggestive of IPD.

Abstract: Intraspecific and interspecific communication and recognition depend on olfaction in widely diverse species of animals. Olfaction, an ancient sensory modality, is based on principles of neural organization and function that appear to be remarkably similar throughout the zoosphere. Thus, the "primitives" of olfactory stimuli that determine the input information of olfaction, the kinds of "molecular images" formed at various levels in the olfactory pathway, and the cellular mechanisms that underlie olfactory information processing are comparable in invertebrates and vertebrates alike. A case in point is the male-specific olfactory subsystem in moths, which is specialized to detect and analyze the qualitative, quantitative, and temporal features of the con-specific females' sex-pheromonal chemical signal. This olfactory subsystem can be viewed, and is here presented, as a model in which common principles of organization and function of olfactory systems in general are exaggerated to serve the requirements of a chemical communication system that is crucial for reproductive success.

Abstract: 1 Projection patterns of olfactory receptor neurons, specifically tuned to the two principal components of the female H virescens sex pheromone blend, and to a third pheromone-like compound of possible antagonistic significance, were examined using a combined electrophysiological and morphological technique 2 The macroglomerular complex consists of four major glomerular subdivisions 3 In the sensillum type containing a receptor neuron detecting the main pheromone component, Z11-16: AL, two cells were present When the sensillum was stimulated with Z11-16:AL, a single axon, stained by a method that selectively stains active neurons, was seen projecting into the large a glomerulus The b glomerulus was innervated by a second neuron in a few double stainings 4 In a second sensillum type, one receptor neuron tuned to the second major pheromone component, Z9-14:AL, was found In these sensilla, one or two receptor neurons of unknown specificity were also observed When the sensillum was stimulated with Z9-14: AL, a single neuron projecting into glomerulus a or two neurons projecting into glomerulus a were most often observed 5 In the third sensillum type, one neuron specifically tuned to Z11-16:AC projected to glomerulus c, and a second cell of unknown specificity projected to the same area 6 The axonal arborizations of different physiological receptor neuron types involved in the detection of the pheromone blend do not display a clearcut morphological separation into different glomeruli in the MGC A separation between neurons detecting attracting and repelling odours was, however, present

Abstract: The present study was designed to investigate whether there is a consistent response in ongoing EEG due to repetitive olfactory stimulation. Two odors of different hedonic quality were presented bilaterally to five male subjects at suprathreshold levels. A room-air blank served as the control stimulus. Each odor was presented six times to each subject in each of three sessions. Electrocortical activity, heart rate, skin conductance and breathing cycle were recorded continuously. EEG variables assessed were difference scores of absolute power in the frequency bands theta, alpha 1, alpha 2 and beta 1 at eight locations. Phenylethyl alcohol was rated pleasant, while valeric acid was judged unpleasant. Within 8 s after stimulus release, valeric acid increased alpha 2 power, whereas phenylethyl alcohol did not. No further frequency bands were affected by olfactory stimulation. These findings suggest that smelling an unpleasant odor leads to a cortical deactivation.

Abstract: Sensory transduction shares common features in widely different sensory modalities. The purpose of this article is to examine the similarities and differences in the underlying mechanisms of transduction in the sensory receptor cells for vision, olfaction, and hearing. One of the major differences between the systems relates to the nature of the stimulus. In both the visual and olfactory systems a quantal mechanism of detection is possible, because the absorption of a photon or the binding of an odorant molecule provides an energy change significantly greater than the thermal noise in the receptor molecule. In hearing, on the other hand, the energy of a phonon is far lower, and detection occurs by a "classical" mechanism. For vertebrate photoreceptors and olfactory receptor cells, sensory transduction employs a G protein cascade that is remarkably similar in the two cases, and that is closely homologous to other G protein signaling cascades. For auditory and vestibular hair cells, transduction operates via a mechanism of direct coupling of the stimulus to ion channels, in a manner reminiscent of the direct gating of post-synaptic ion channels in various synaptic mechanisms. The three classes of sensory receptor cell share similarities in their mechanisms of adaptation, and it appears in each case that cytoplasmic calcium concentration plays a major role in adaptation.

Abstract: General Methods in Chemosensory Research Euthanasia, I. Ramirez Collection of Taste Tissue from Fish and Amphibians, J. H. Teeter Collection of Taste Tissue from Mammals, A. I. Spielman and J. G. Brand Insects: Isolation of Olfactory Sensilla and Collection of Sensillum Lymph, G. Ziegelberger Surgical Anatomy of Olfactory Organ and Tissue Collection Methods in Vertebrates, T. Kurahashi and D. Restrepo Collection of Human Olfactory Tissue, L. D. Lowry and E. A. Pribitkin Surgical Removal of the Vomeronasal Organ and Its Verification, C. J. Wysocki and L. M. Wysocki Denervation and Reinnervation of the Tongue, B. Oakley The Lingual Slice Preparation, Isolated Taste Cells, and Dye Injections in Mudpuppy, A. Bigiani, D. A. Ewald, and S. D. Roper Cell Dissociation Methods for Patch Clamp Electrophysiological Studies of Vertebrate Olfactory Receptor Neurons, A. H. Kahn and S. Firestein Tissue Culture of Rat Taste Buds, C. Ruiz, M. McPheeters, and S. C. Kinnamon Olfactory Receptor Neuronal Cultures, G. V. Ronnett Methods for Airborne and Aqueous Stimulus Delivery in Olfactory Research, J. S. Kauer and S. Firestein Imaging Methods in Chemosensory Research Videomicroscopy and Image Processing, I. J. Miller and S. L. Hayes Transmission Electron Microscopy of Gustatory Epithelium, H. H. Crowley and J. C. Kinnamon Scanning and Transmission Electron Microscopy of Olfactory Epithelia, B. Ph. M. Menco Analysis of Taste Bud Ultrastructure by Serial Sectioning and Three-Dimensional Reconstruction, S. M. Royer and J. C. Kinnamon Immunohistochemistry, C. DellaCorte IP3 Autoradiography of Taste Receptor Cells, P. A. Hwang In Situ Hybridization, H. Schmale and M. Behrens Biochemical Methods in Chemosensory Research Membrane Preparation and Subcellular Fractionation, D. L. Kalinoski Preparation of Olfactory Cilia, R. R. H. Anholt The Use of the Spiny Lobster as a Tool for the Study of Chemosensory Biochemistry, H. G. Trapido-Rosenthal Receptor Binding and Solubilization, D. L. Kalinoski Western Blotting, R. Bruch and Fe. C. Abogadie Approaches for Monitoring Rapid Kinetics of Second Messenger Signaling, E. Tareilus, I. Boekhoff, A.I. Spielman, and H. Breer Second Messenger Assays, A. I. Spielman, H. Nagai, G. Sunavala, M. Dasso, T. Huque, and J. G. Brand Electrophysiological and Biophysical Methods in Chemosensory Research General Methods Reconstitution of Chemoreceptor Proteins in Planar Lipid Bilayers, A. M. Feigin, M. Zviman, and J. H. Teeter Data Acquisition in Electrophysiology, V. E. Dionne Whole Nerve and Single Unit Recordings Taste Nerve Recording from a Voltage-Clamped Receptive Field, J. A. DeSimone, G. Heck, and Q. Ye Whole Nerve and Single Fiber Recordings in Frog, T. Miyamoto and T. Sato Single Unit Electrophysiological Recordings from Crustacean Chemoreceptor Neurons, C. D. Derby Olfactory and Taste Recordings in Fish, J. Caprio Taste Nerve Recordings in Rodents, M. E. Frank Trigeminal Nerve Recordings in Rodents, B. P. Bryant Whole Nerve and Single Fiber Recordings in Non-Human Primates, G. Hellekant and T. W. Roberts Electrophysiology of the Vomeronasal Organ and Accessory Olfactory System, M. Meredith Patch-Clamping Patch-Clamping of Taste Cells in the Mudpuppy, T. A. Cummings and S. C. Kinnamon Patch-Clamping Recording from Taste Receptor Cells of Channel Catfish and Larval Tiger Salamander, J. H. Teeter Patch-Clamping of Taste Cells in Hamster and Rat, T. A. Gilbertson Patch-Clamping of Taste Cells in Mouse, J. F. MacDonald, I. Mody, M. W. Salter, and A. I. Spielman Loose-Patch Recording from Taste Buds in Situ, B. Lindemann Patch-Clamping Lobster Olfactory Receptor Cells, B. W. Ache, D. A. Fadool, and A. Zhainazarov Patch-Clamping of Whole Olfactory Cilia, S. J. Kleene Patch-Clamping Techniques for Vertebrate Olfactory Receptor Cells, G. Lowe, T. Nakamura, and G. H. Gold Single Unit and Electroantennogram Recordings in Insect Olfactory Organs, K.-E. Kaissling Patch-Clamping of Olfactory Cells in Insects, F. Zufall Imaging of Intracellular Calcium in Chemosensory Receptor Cells, D. Restrepo, M. Zviman, and N. E. Rawson Videorate Imaging of Potentiometric Dyes in Olfactory Research, J. S. Kauer Methods to Study Flow Dynamics in Olfaction, P. W. Scherer, K. Keyhani, I. Hahn, and M. Mozell Applications of Molecular Biology to Chemosensory Research Cloning of Gustatory cDNAs and Analysis of Their Pattern of Expression, P. J. McKinnon, S. K. McLaughlin, and R. F. Margolskee Cloning of Odorant Receptors, E. R. Liman and L. B. Buck List of Critical References for Techniques Not Covered

Abstract: The brain of the locust Schistocerca gregaria contains a nitric oxide synthase (NOS) that has similar properties to mammalian neuronal NOS. It catalyses the production of equimolar quantities of nitric oxide (NO) and citrulline from l-arginine in a Ca2+/calmodulin- and NADPH-dependent manner and is inhibited by the Nomega-nitro and Nomega-monomethyl analogues of l-arginine. In Western blots, an antiserum to the 160 kDa rat cerebellar NOS subunit recognises a locust brain protein with a molecular mass of approximately 135 kDa. NOS is located in several parts of the locust brain, including the mushroom bodies, but it is particularly abundant in the olfactory processing centres, the antennal lobes. Here it is present in two groups of local interneurones (a pair and a cluster of about 50) that project into the neuropile of the antennal lobes. The processes of these neurones terminate in numerous glomerulus-like structures where the synapses between primary olfactory receptor neurones and central interneurones are formed. NOS-containing local interneurones have also been identified in the mammalian olfactory bulb, suggesting that NO performs analogous functions in locust and mammalian olfactory systems. As yet, nothing is known about the role of NO in olfaction, but it seems likely that it is involved in the processing of chemosensory input to the brain. The locust antennal lobe may be an ideal 'simple' system in which this aspect of NO function can be examined.

Abstract: A central problem in sensory system biology is the identification of the signal transduction pathways used in different sensory modalities. Genetic analysis of transduction mutants provides a means of studying in vivo the contributions of different pathways. This report shows that odorant response in one olfactory organ of Drosophila melanogaster depends on the norpA phospholipase C (EC 3.1.4.3) gene, providing evidence for use of the inositol 1,4,5-trisphosphate (IP3) signal transduction pathway. Since the norpA gene is also essential to phototransduction, this work demonstrates overlap in the genetic and molecular underpinnings of vision and olfaction. Genetic and molecular data also indicate that some olfactory information flows through a pathway which does not depend on norpA.

Abstract: Recent evidence suggests that, like nitric oxide (NO), carbon monoxide (CO), another activator of soluble guanylyl cyclase, may serve as an intercellular messenger in the brain. Heme oxygenase, which converts heme to biliverdin and CO, is abundantly expressed in the brain and is localized to discrete neuronal populations. However, evidence for the actual generation of CO by neurons is lacking. Heme oxygenase-2 immunoreactivity is abundantly present in olfactory receptor neurons where it essentially colocalizes with immunoreactivity to soluble guanylyl cyclase, the target of CO action. To examine the generation of CO by neurons, we measured CO production directly and determined its relationship to cyclic GMP levels in cultured rat olfactory receptor neurons. This system has the advantage of not having measurable NO production, which could confound results since NO is a more potent activator of guanylyl cyclase than CO. Metabolic labeling experiments permitted the direct measurement of 14CO production by neurons in vitro. CO release parallels endogenous cyclic GMP concentrations with its peak at the immature stage of neuronal differentiation in culture. Cyclic GMP production is inhibited by zinc protoporphyrin-9 and zinc deuteroporphyrin IX 2,4-bis glycol, inhibitors of heme oxygenase, indicating that CO is an endogenous regulator of soluble guanylyl cyclase activities in these cells. Transforming growth factor-beta 2, an olfactory neurogenic factor, specifically shows a negative effect on CO release in olfactory receptor neurons. These results indicate that CO may serve as a gaseous neuronal messenger linked to cyclic GMP production and suggests its involvement in developmental processes of the olfactory receptor neuron.

Abstract: Olfactory auras accompany some cases of epilepsy. Several aspects of olfactory function, including sensitivity, also may be altered. We reviewed the literature on these topics, as well as studies evaluating the influences of temporal lobe resection and other seizure management procedures on olfactory function. We concluded that: (a) despite several studies, the prevalence of olfactory auras in epilepsy is unknown, with estimates ranging from 30%; (b) epilepsy appears to cause a generalized decrease in olfactory functioning, although increased sensitivity may occur in some epileptic patients at some time in the preictal period; (c) other sensory modalities are also affected by the epileptic process which, in some cases, involve limbic-related temporal lobe structures; (d) many of the olfactory deficits previously attributed to temporal lobe resection actually exist preoperatively; (e) a taste/flavor confusion exists in the reporting of taste auras; (f) unpleasant auras are associated with hyperresponsiveness of neurons, which may explain why most epilepsy-related olfactory auras are described as "bad"; and (g) interesting parallels exist between the effects of the neuroendocrine system on seizure activity and olfactory function.

Abstract: Freshwater crayfish have well-developed olfactory systems with an array of receptors that project exclusively to areas in the brain that are functionally specialized for the processing of odors. The accessory lobes are large bilateral areas of neuropil that are anatomically associated with the olfactory lobes. The accessory lobes receive no primary afferents and do not contain the endings of motor efferents; thus, their role in olfaction is still obscure. Intracellular dye filling of interneurons in the deutocerebral commissure in the crayfish brain has shown that they end bilaterally in glomeruli in the accessory lobes, have cell somata in a dorsal cluster medial to the olfactory lobes, and have unilateral projections to the deutocerebral commissure neuropil. Each deutocerebral commissure interneuron has only 6 to 15 output glomeruli in each accessory lobe and does not share glomeruli with other deutocerebral commissure interneurons. The deutocerebral commissure interneurons converge with the dorsal giant serotonin neurons in the accessory lobe glomeruli. Deutocerebral commissure interneurons can be separated into classes according to their projections to the protocerebrum, central body, and deutocerebrum. Physiological responses of the deutocerebral commissure interneurons following photic stimulation of the eyes and electrical stimulation of the second antennae lead to the conclusion that the deutocerebral commissure represents an input to the accessory lobes from the protocerebral neuropils and that visual and tactile inputs are included in the processing performed in the accessory lobes. © 1995 Wiley-Liss, Inc.

Abstract: We have identified another Drosophila GTP-binding protein (G protein) alpha subunit, dGq alpha-3. Transcripts encoding dGq alpha-3 are derived from alternative splicing of the dGq alpha locus previously shown to encode two visual-system-specific transcripts [Lee, Y.-J., Dobbs, M.B., Verardi, M.L. & Hyde, D.R. (1990) Neuron 5, 889-898]. Immunolocalization studies using dGq alpha-3 isoform-specific antibodies and LacZ fusion genes show that dGq alpha-3 is expressed in chemosensory cells of the olfactory and taste structures, including a subset of olfactory and gustatory neurons, and in cells of the central nervous system, including neurons in the lamina ganglionaris. These data are consistent with a variety of roles for dGq alpha-3, including mediating a subset of olfactory and gustatory responses in Drosophila, and supports the idea that some chemosensory responses use G protein-coupled receptors and the second messenger inositol 1,4,5-trisphosphate.

Abstract: Certain medications and environmental agents are known to adversely affect chemosensation. We report data from 712,000 respondents aged 20 to 79 to the National Geographic Smell Survey that suggest that exposure to the factory workplace adversely affects the sense of smell, and that these effects interact with age. Men and women with histories of factory work reported poorer senses of smell relative to other workers. They also demonstrated objective evidence of greater impairment in odor detection. These effects were greater for men. Factory workers of all ages more frequently reported olfactory loss secondary to chemical exposure and head injury than did workers in other environments. The highest relative risk of olfactory problems secondary to head injury was in the oldest women factory workers. Thus, olfaction may behave as other senses do: Age, sex, and exposure to noxious events or agents interact to produce sensory deficits.

Abstract: 1. The specificity and sensitivity of the olfactory organ of adult zebrafish, Danio rerio, to selected amino acid, bile acid, and steroid odorants were characterized using the electro-olfactogram recording technique. The olfactory organ was responsive to 28 of the 29 odorants tested. 2. All of the 100 microM amino acid and bile acid stimulants elicited a negative-going response that was significantly greater than the response to the artificial fresh-water control. The general pattern of relative stimulatory effectiveness established for the amino acid stimuli was neutral amino acids > basic amino acids > acidic amino acids > imino acids. The general pattern of relative stimulatory effectiveness of 100 microM bile acid stimuli was taurine-conjugated bile acids > glycine-conjugated bile acids approximately non-conjugated bile acids. The responses to the most stimulatory bile acid odorants were up to 40% larger than the responses to the most stimulatory amino acid odorants. 3. The response threshold for cysteine and taurocholic acid, the most stimulatory of the amino acid and bile acid stimuli tested, was approximately 10(-8) M. Females are significantly more sensitive to these odorants than males.

Abstract: In chemosensory systems, a variety of lipophilic ligand-binding proteins have been found in saliva or nasal mucus. Lipophilic stimulants reach the receptor membrane, carried by these proteins. An acidic 14-kDa protein purified in the blowfly, Phormia regina, belongs to the insect pheromone-binding protein superfamily, but unlike other lipophilic ligand-binding proteins in insect or vertebrate chemosensory systems, it was distributed in both taste and olfactory organs. A similar protein was also isolated in Drosophila melanogaster. Considering their distributions, cDNA sequences and structural features, we concluded that these proteins belong to a unique subfamily whose members have convergently evolved for a common function required for both senses of taste and olfaction. By an electrophysiological experiment using antiserum, we also suggested that these proteins carry fragrant components of natural foods in taste systems as well as in olfactory systems.

Abstract: Primary cell cultures from human fetal olfactory neuroepithelium have been isolated, cloned, and propagated in continuous in vitro culture for approximately 1 year. The two clones we report here synthesize both neuronal proteins and olfactory-specific markers as well as the putative olfactory neurotransmitter, carnosine. In addition, patchclamp experiments reveal that these cells are electrically excitable. Following exposure to a panel of aromatic chemicals one of the cell cultures shows a specific increase in intracellular cAMP, indicating that some degree of functional maturity is expressed in vitro. The results suggest that these cells originate from the “stem cell” compartment that gives rise to mature olfactory receptor neurons. These long-term cell cultures represent models that will be useful in studying the mechanism(s) of olfaction and the regulation of olfactory neurogenesis and differentiation.

Abstract: OBJECTIVE: The hypothesis tested was that patients with severe eating disorders would demonstrate olfactory identification deficits as a result of zinc deficiency or malnutrition. METHOD: The University of Pennsylvania Smell Identification Test (UPSIT) was administered to 27 hospitalized female patients with anorexia nervosa and 50 normal control female subjects. For a subgroup of patients, serum zinc levels and body mass indices were obtained at pre- and post-nutritional repletion phases. RESULTS: UPSIT scores for patients with eating disorders were equivalent to normal control subjects in spite of the fact that the patients were nutritionally compromised as determined by body mass index. Serum zinc levels were not significantly different at pre- and post-nutritional repletion. CONCLUSIONS: In contrast to patients with schizophrenia, patients with severe eating disorders have intact olfactory function. This finding suggests that transient metabolic or nutritional disturbances alone cannot account for previously reported olfactory deficits.