Showing papers on "Olfactory system published in 1976"
TL;DR: In animals with injected HRP confined within the main bulb, perikarya retrogradely labeled with the protein in the ipsilateral forebrain were observed in the anterior prepyriform cortex, horizontal limb of the nucleus of the diagonal band, and far lateral preoptic and rostral lateral hypothalamic areas.
Abstract: The axoplasmic retrograde transport of horseradish peroxidase (HRP) from axon terminals to their parent cell bodies and histochemical fluorescence microscopy have been used to study the ipsilateral centrifugal fibers to the olfactory bulbs and anterior olfactory nucleus in the rabbit. Focal injections of peroxidase were placed unilaterally into the main or accessory olfactory bulb or into the anterior olfactory nucleus. In animals with injected HRP confined within the main bulb, perikarya retrogradely labeled with the protein in the ipsilateral forebrain were observed in the anterior prepyriform cortex horizontal limb of the nucleus of the diagonal band, and far lateral preoptic and rostral lateral hypothalamic areas. Brain stem cell groups that contained HRP-positive somata include the locus coeruleus and midbrain dorsal raphe nucleus. Except for the prepyriform cortex, the basal forebrain structures with labeled perikarya correlate well with locations of cell bodies containing acetylcholinesterase and choline acetyltransferase. These somata may represent a cholinergic afferent system to the main olfactory bulb. Peroxidase-labeled cell bodies in the locus coeruleus and midbrain raphe are indicative of noradrenergic and serotonergic innervations respectively of the olfactory bulb. In rabbits in which peroxidase was injected or diffused into the accessory olfactory bulb and anterior alfactory nucleus, HRP-positive somata were identified in the prepyriform cortex bilaterally, the horizontal limb of the diagonal band nucleus, lateral hypothalamic region, nucleus of the lateral olfactory tract, corticomedial complex of the amygdala, mitral and tufted cell layers of the ipsilateral main olfactory bulb, locus coeruleus, and the midbrain raphe. Evidence for centrifugal fibers to the accessory olfactory bulb from the corticomedial complex of the amygdala, locus coeruleus, and possibly the nucleus of the lateral olfactory tract and midbrain raphe is discussed. A similar distribution of labeled perikarya in the forebrain and brain stem was seen in rats in which peroxidase injected into the main olfactory bulb had spread into the accessory bulb and anterior olfactory nucleus. Histochemical fluorescence microscopy of the main and accessory olfactory bulbs in the rabbit and rat revealed fine caliber, green fluorescent fibers and varicosities predominantly in the granule cell layer and less so among cells in the glomerular layer. In sections through the root of the main olfactory bulb, a similar fluorescence was seen in the deep half of the plexiform layer of the pars externa of the anterior alfactory nucleus. These fluorescent fibers likely represent the noradrenergic innervation of the olfactory bulbar and retrobulbar formations. A fluorescent yellow hue was observed in the glomerular layer of the main bulb and may signify a serotonergic innervation of this lamina...
154 citations
TL;DR: The effects of mercury and copper on the olfactory response of rainbow trout were studied by perfusing HgCl2 and CuSO4 solutions through theOlfactory organs while recording the Olfactory bulbar electrical responses to the standard stimulant, L-serine.
Abstract: The effects of mercury and copper on the olfactory response of rainbow trout (Salmo gairdneri) were studied by perfusing HgCl2 and CuSO4 solutions through the olfactory organs while recording the o...
114 citations
1 Jan 1976
TL;DR: Until recently, the frog telencephalon, like those of other nonmammalian vertebrates, was believed to be dominated by the olfactory system, but Herrick (1948) conceived of the amphibian dorsal thalamus as a nucleus sensitivus integrating multimodal afferents and lacking functional subdivisions.
Abstract: Until recently, the frog telencephalon, like those of other nonmammalian vertebrates, was believed to be dominated by the olfactory system. This misconception may originally have been derived from the relatively large size of the olfactory bulbs and tracts. It was thought that all regions of the telencephalon received olfactory afferents. Domination of the telencephalon by olfaction left little room for telencephalic representation of other sensory modalities: a case in point is vision. The optic tectum was considered to be most important part of the visual system of nonmammalian vertebrates; diencephalic and telencephalic structures were presumed to be little involved in this modality. Herrick (1948) conceived of the amphibian dorsal thalamus as a nucleus sensitivus integrating multimodal afferents and lacking functional subdivisions.
86 citations
TL;DR: It is suggested that the pattern of response decrement within the bulb represents a case of stimulus-specific habituation in a simple cortical subsystem and is well worth future investigation as a model of neural plasticity.
74 citations
TL;DR: Results indicate that stimulation to the lateral olfactory tract enhances liberation of glutamate from the tract nerve terminals.
Abstract: — Thin sections prepared from the olfactory cortex of the guinea pig were incubated in a medium containing [14C]glutamate, and release of radioactive compounds and electrical activity were subsequently examined in the presence of l-cysteate. The postsynaptic potential was almost completely suppressed in the medium containing l-cysteate, whereas the presynaptic potential was unaffected. Repetitive stimulation of the excitatory input of the lateral olfactory tract enhanced release of radioactive glutamate. The facilitatory effect of lateral olfactory tract stimulation increased with increase in stimulus frequency and was dependent on calcium. Release of radioactive gluiamine was not enhanced by lateral olfactory tract stimulation. Phenobarbitone sodium markedly depressed both the postsynaptic potential and the effect of lateral olfactory tract stimulation on glutamate release. These results indicate that stimulation to the lateral olfactory tract enhances liberation of glutamate from the tract nerve terminals.
65 citations
TL;DR: Differences between the olfactory organs of the two species investigated related only to the topography and quantitative distribution of the epithelia.
Abstract: The epithelia of the olfactory organ of two cyprinodontoid fish species were studied both by transmission and scanning electron microscopy. The relatively flat floor of the organ is covered by sensory and nonsensory epithelia. The latter is distributed in the form of bands or ridges separating distinct areas of sensory epithelium. Differences between the olfactory organs of the two species investigated related only to the topography and quantitative distribution of the epithelia. Their ultrastructural features are very similar. The nonsensory stratified squamous epithelium contains numerous goblet cells and surface cells provided with microridges. A hypothetical function of the microridges is discussed. The sensory epithelium consists mainly of basal, supporting, and two types of sensory cells, i.e., ciliated and microvillous receptor cells. The cilia exhibitapredominant 9+0 microtubule pattern. Both epithelia are covered by a mucus layer in which all surface structures seem to be embedded. The possible nature, origin, and movement mechanisms of the mucus are discussed.
61 citations
TL;DR: A possible presynaptic depolarizing action of a GABA‐like transmitter giving rise to presynptic inhibition and the late N‐wave is discussed in terms of a possible multisynaptic origin.
Abstract: 1. Field potentials were evoked from rat olfactory cortex slices in vitro at room temperature by lateral olfactory tract stimulation. At very slow stimulation rates (less than 0-1 Hz) a delayed negative wave (late N-wave) was found to follow the first negative wave (N-wave). This late N-wave started 30 msec after the stimulus and lasted for 50-150 msec. 2. Low Ca2+/high Mg2+ medium abolished the late N-wave more rapidly than the N-wave, suggesting a possible multisynaptic origin. 3. The GABA antagonist bicuculline (10(-6) M) abolished the late N-wave without affecting the N-wave. 4. During the late N-wave, both the tract action potential and the N-wave to a second stimulus were reduced. This was attributed, at least in part, to collision with antidromic action potentials which could be detected during the late N-wave. 5. These findings are discussed in terms of a possible presynaptic depolarizing action of a GABA-like transmitter giving rise to presynaptic inhibition and the late N-wave.
55 citations
1 Jan 1976
52 citations
TL;DR: This chapter discusses the chemical signaling systems in primates and other mammals and investigates the role of olfactory mechanisms in the behavioral interactions of the pair.
Abstract: Publisher Summary This chapter discusses the chemical signaling systems in primates and other mammals. The importance of olfaction in the life of numerous primate species under natural conditions is reviewed. The emission and reception of olfactory signals is clearly apparent from the observation of their behavior patterns. The research on the rhesus monkey under laboratory conditions suggested that the male receives information about the hormonal status of his female partner by olfactory pathways. Males made temporarily anosmic failed to detect increases in the attractive properties of their partners, but did so when their olfactory acuity returned. To demonstrate the role of olfactory mechanisms in the behavioral interactions of the pair, it is necessary to conduct experiments to exclude the role of visual signals, and also to exclude the role of afferent stimulation. The olfactory signal appeared to be present in the vaginal secretions of estrogen-treated females. The behaviorally active components are extractable into ether and have acidic properties: they are identified by gas chromatography and mass spectrometry as a series of volatile, short-chain aliphatic acids.
TL;DR: Electrophysiological evidence is provided for a topographical projection of the olfactory receptor sheet onto the Olfactory bulb, and it is suggested that the projections onto different bulbar cells vary in degree of localization.
Abstract: Three olfactory nerve branches respectively subserving either a medial, an intermediate, or a lateral region of the dorsal olfactory receptor sheet of the bullfrog Rana catesbeiana were electrically stimulated with bipolar platinum hook electrodes. Extracellular single unit responses from 93 second-order cells in different regions of the olfactory bulb were recorded with metal-filled glass micropipets. The excitatory responsiveness of each unit to the stimulation of each of the three nerve branches (response profile) was determined. Some units were sensitive to stimulation of each of the three nerve branches, thus suggesting a wide projection from the entire receptor sheet. On the other hand, other units were more selective. Of this latter group, units in the lateral bulb were excited by nerve branches subserving the more lateral regions of the receptor sheet; units in the medial bulb were excited by the nerve branches subserving the more medial regions of the receptor sheet. These data provide electrophysiological evidence for a topographical projection of the olfactory receptor sheet onto the olfactory bulb, and further suggest that the projections onto different bulbar cells vary in degree of localization.
TL;DR: Olfactory threshold did not vary with the presence or absence of optic involvement and correlated poorly with the degree of disability among the MS patients, and available biochemical evidence suggests that, as postulated by LUMSDEN, sparing of olfactory tracts may in part be related to the relatively lower basic protein content of these structures.
Abstract: Serial binary dilutions of amyl acetate and nitrobenzene were used in a double-blind test to determine olfactory acuity of 40 multiple sclerosis (MS) patients. Similar determinations were made on 24 age- and sex-matched controls. Results of repeated measurements on 18 patients indicated that the methodology was reliably reproducible. When mean olfactory threshold on MS patients was compared with that of the controls no differences could be found. Among the MS patients, olfactory threshold did not vary with the presence or absence of optic involvement and correlated poorly with the degree of disability. These results are in disagreement with those of Wender and Szmeja who reported olfactory dysfunction in 18 out of 52 MS patients. Our findings are compatible with the observations of Zimmerman and Netsky who failed to find any plaques in olfactory tracts of MS brains. The significance of this disparity between involvement of optic and olfactory systems, both of which contain central myelin, is discussed. Available biochemical evidence suggests that, as postulated by Lumsden, sparing of olfactory tracts may in part be related to the relatively lower basic protein content of these structures.
TL;DR: The olfactory organ has an epithelium containing many sense cells and a large subepithelial mass of receptor cells that form patent connections between the ciliated cavity and the surface or have a ciliated ending at the surface.
Abstract: The olfactory organ has an epithelium containing many sense cells and a large subepithelial mass of receptor cells. The epithelium includes cells with cupshaped, ciliated endings, and hollow, flask-shaped sense cells with ciliated cavities that open to the surface through a small pore. Below the epithelium are large hollow cells with ciliated cavities and distal processes that either form patent connections between the ciliated cavity and the surface or have a ciliated ending at the surface. There are many synapses between processes in the olfactory nerve. The possible chemosensory function of the olfactory organ is discussed.
TL;DR: There was an immediate and sharp drop in the level of carnosine in the olfactory bulb of rats on the histidine‐free diet and anserine was lower relative to the controls, but actually increased in absolute value.
Abstract: Young adult male rats were fed purified diets supplying the maintenance level of the essential amino acids or the same diet devoid of histidine. Animals were sacrificed after 2, 4, 6 and 8 weeks on these diets and olfactory bulbs, whole brains and breast muscle removed for analysis of free histidine and histidinecontaining dipeptides. There was an immediate and sharp drop in the level of carnosine in the olfactory bulb of rats on the histidine-free diet. By 8 weeks only very small amounts of this dipeptide remained. The carnosine concentration in the olfactory bulbs of the rats receiving the maintenance level of histidine also decreased in comparison with the level maintained on the stock diet; this is believed to reflect the much reduced amount of histidine in the former as compared to the latter diet. Homocarnosine disappeared completely from whole brains of rats within 2 weeks on the histidine-free diet. Muscle carnosine decreased in both absolute terms and relative to the controls. Anserine was lower relative to the controls, but actually increased in absolute value. Histidine deficiency may be used to study the role of carnosine in olfactory function.
TL;DR: The difference in sensitivity between the two groups of neurones to these agonists was much greater: the Renshaw cells were much more sensitive to N-methyl-D-aspartate and the dorsal interneurones to kainate, which would be too small to interact with the glutamate receptor.
Abstract: THE possibility that L-glutamate and L-aspartate are excitatory transmitters in the CNS is supported by neurochemical and neurophysiological evidence1. The problems of identifying particular synapses that are excited by one or the other of these dicarboxylic amino acids, and distinguishing between the two receptors are, however, more difficult. At the recent International Meeting of Neurochemistry (September 1975) Graham summarised some of the evidence favouring distinct functions for the two amino acids, concentrating on the possible transmitter role of L-aspartate. For example, a higher content of this amino acid is found in the ventral than in the dorsal grey matter of the spinal cord2, aortic occlusion leads to loss of aspartate content and degeneration of small neurones3, reduction in aspartate content is seen in the spinal cord after section of dorsal roots4 and in the olfactory cortex after olfactory bulbectomy5, which also decreases glutamate. Renshaw cells are slightly more sensitive to the ionotophoretic administration of L-aspartate while the reverse is true of interneurones of the dorsal spinal horn6. It is possible that L-glutamate and L-aspartate, being flexible molecules, fold or unfold and could interact with either receptor and McCulloch et al.7 accordingly used kainate, a conformational restricted analogue of glutamic acid, which would be unlikely to fold to occupy the aspartate receptor, and N-methyl-D-aspartate, which would be too small to interact with the glutamate receptor (Fig. 1). The difference in sensitivity between the two groups of neurones to these agonists was much greater: the Renshaw cells were much more sensitive to N-methyl-D-aspartate and the dorsal interneurones to kainate7.
TL;DR: In front of the olfactory organ in the northeastern Pacific hagfishes Eptatretus stoutii, E. deani, and Myxine circifrons there is a valve that may function to direct water in between the o aroma laminae, and cilia show a tendency for a dislocation of one pair of the microtubules toward the center of the cilium.
Abstract: In front of the olfactory organ in the northeastern Pacific hagfishes Eptatretus stoutii, E. deani, and Myxine circifrons there is a valve that may function to direct water in between the olfactory laminae. In Myxine circifrons the well developed valve is supposed to act alone, whereas the smaller valve in the two species of Eptatretus studied is supposed to act together with the horizontal extensions of the median olfactory lamina. No significant differences were found between the investigated species by ultrastructural examination. In the olfactory epithelium the supporting cells are provided with microvilli and generally contain a great amount of light secretory granules. Both ciliated olfactory receptor cells and microvillous olfactory receptor cells are present. The cilia show a 9 + 0 arrangement of the microtubules with a tendency for a dislocation of one pair of the microtubules toward the center of the cilium. These remarkable features of the olfactory receptor cells, not yet seen in other vertebrates, appear to be a character common to the myxinoid cyclostomes.
TL;DR: A multichanneled hypothalmic modulation of olfactory input is suggested, quite similar to that consequent to hypothalmic stimulation, with a common postsynaptic neuronal pool with axons of hyopothalmic origin.
TL;DR: The rostral parts of the brain in Calamoichtkys calabaricus, a brachiopterygian fish, show some similarities with actinopterygians, as well as with lungfishes and amphibians, and this study includes a histological analysis of the optic tectum, pretECTum, diencephalon and the olfactory system.
Abstract: The rostral parts of the brain in Calamoichtkys calabaricus, a brachiopterygian fish, show some similarities with actinopterygians, as well as with lungfishes and amphibians. This study includes a histological analysis of the optic tectum, pretectum, diencephalon and the olfactory system.
1 Jan 1976
TL;DR: This chapter discusses the carnosine, β-alanyl- L -histidine, in the olfactory nerve, and reports that destruction of these bulbar synaptic terminals is reported to result, in rapid retrograde degeneration of the Olfactory chemoreceptor neuron cell bodies in the nasal epithelium.
Abstract: Publisher Summary This chapter discusses the carnosine, β-alanyl- L -histidine, in the olfactory nerve. The approach to the problem was to evaluate the effect of selective denervation procedures on biochemical parameters associated with various transmitter candidates. The primary olfactory pathway is particularly suited for this kind of study because the olfactory receptor neuron cell bodies are anatomically removed from their synapses. The cell bodies lie in the nasal olfactory epithelium outside the cranial vault while their axons penetrate the cribriform plate to synapse with mitral cell dendrites and periglomerular cells in the olfactory bulb. Destruction of the neuronal cell bodies in the nasal epithelium results in the degeneration of their synaptic terminals in the bulb. In addition, destruction of these bulbar synaptic terminals is reported to result, in rapid retrograde degeneration of the olfactory chemoreceptor neuron cell bodies in the nasal epithelium. The olfactory bulbs and epithelium of a wide variety of mammals have been shown to have high levels of carnosine relative to other brain areas. In rodents, carnosine is generally present at 1–2 nmoles/mg tissue in the olfactory pathway, which is 10–50 times the concentration found in other brain areas.
TL;DR: The results suggest the involvement of the olfactory system in the thermoregulation of rats and suggest the role of canine coronavirus in this process.
TL;DR: Experimental resection of the Olfactory nerve in the homing pigeon induces a total degeneration of the nerve and olfactory epithelium, and the ultrastructural features of the mucosa andOlfactory axons are similar to those of normal ones.
Abstract: Experimental resection of the olfactory nerve in the homing pigeon induces a total degeneration of the nerve and olfactory epithelium. The orthograde degenerative process starts before the retrograde one. Ten days after resection, new neurons begin to differentiate from the basal cells. The axon forms earlier than the distal dendritic process, and the speed of growth increases slowly. The regenerated axons only reach the bulb in the 5th month. Two months after resection the olfactory epithelium is similar to that of the intact control side. The ultrastructural features of the mucosa and olfactory axons are similar to those of normal ones.
Journal Article•
TL;DR: In 8 patients with disturbed olfactory function suffering from liver cirrhosis a comparison of the olfactometrical findings with activity of GOT and GPT in the serum and the serum bilirubin content showed a correlation between possibilitiy of smelling and serum bilIRubin level.
Abstract: In olfacto-odorimetrical examinations of 32 patients with chronic liver diseases (18 female and 14 male patients at the age of 23 to 77 years) 13 patients with a disturbed olfactory function were found. With one exclusion these patients suffered from liver cirrhosis. On the basis of the anamnesis in 10 of these patients a causal connection between disturbance of smelling and liver disease could be assumed. Out of this group with chronic active hepatitis of 10 patients only 1 patient had a disturbed olfactory function. In 8 patients with disturbed olfactory function suffering from liver cirrhosis a comparison of the olfactometrical findings with activity of GOT and GPT in the serum and the serum bilirubin content showed a correlation between possibilitiy of smelling and serum bilirubin level. Possible causes of appearing olfactory disturbances are demonstrated in short.
Journal Article•
TL;DR: In the olfactory epithelium of Elasmobranchs, together with the supporting cells crowned by cilia, numerous goblet cells were observed and this mucus represents an intermediate milieu for the molecules of odorous substances.
Abstract: The structure of the receptor cells in the olfactory organ of the rays Raja clavata and Dasyatis pastinaca and spiny dogfish Squalus acanthias is similar to that of the olfactory cells in other Vertebrates, although their tops are invariably crowned by microvilli, not flagella. In the peripheral process of these cells of Elasmobranchs and some other vertebrates represent a special type of the olfactory receptors which originated as the result of differentiation of primary olfactory cells supplied both by flagella and by microvilli. In the olfactory epithelium of Elasmobranchs, together with the supporting cells crowned by cilia, numerous goblet cells were observed. These glands produce a mucus which protects the olfactory epithelium of Elasmobranchs from the direct contact with the sea water. Similar to that in all other vertebrates, this mucus represents an intermediate milieu for the molecules of odorous substances.
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