| 1. |
- Aramant, Robert, et al.
(författare)
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Distribution of monoaminergic neurons in the nervous system of non-Malacostracan crustaceans
- 1976
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Ingår i: Cell and Tissue Research. - 1432-0878. ; 166, s. 1-24
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Tidskriftsartikel (refereegranskat)abstract
- A comparative investigation of the distribution of monoaminergic neurons in non-malacostracan crustaceans was performed with the histochemical fluorescence method of Falck-Hillarp.Two fluorophores were found: the more widespread of the two emits a green fluorescence; and the more sparsely distributed emits a yellow to brown-yellow fluorescence.Specific green fluorescent areas were shown to exist in the protocerebrum. The central body and the optic ganglia of the compound eye (where present) are always fluorescent. Moreover, the centre of the nauplius eye may have a green fluorophore, as in ostracods, and a neuropile area, here called the frontal area. These neuropile centres are known from ordinary histological studies of the nervous system. In addition, there are specific monoaminergic centres, such as the so-called dorsal area of phyllopods and anostracans as well as the copepod specific areas. Specific monoaminergic areas appear in the deutocerebrum and the suboesophageal ganglion where they are particularly well developed.Presumed sensory neurons in the cavity receptor organ of Artemia salina are shown to be monoaminergic. Monoaminergic sensory neurons have not been described previously in Arthropods.Presumed motor innervation of hind-gut and trunk muscles is also found, and it is concluded that in crustaceans neurons of every type (sensory, internuncial, motor) may be monoaminergic.
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| 2. |
- Aramant, Robert, et al.
(författare)
-
Monoaminergic neurons in the nervous system of crustaceans.
- 1976
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Ingår i: Cell and Tissue Research. - 1432-0878. ; 170, s. 231-251
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Tidskriftsartikel (refereegranskat)abstract
- Certain neurons in the nervous system of the malacostracan crustaceans give rise to a predominantly green and a sparse yellow fluorophore in the histochemical fluorescence method of Falck-Hillarp. The same applies to the whole of Crustacea. The green fluorophore is probably a catecholamine; the yellow to brown-yellow has not yet been identified.The biogenic amine responsible for the green fluorescence, besides being found in diffusely distributed fibres, also appears in distinct areas of fibre concentrations in the central nervous system. The protocerebrum of the malacostracans contains three areas: the central body and two areas in the top of the brain, one anterior and one posterior. The latter two are not recognized as separate areas in ordinary histological preparations. In addition, the optic neuropiles are fluorescent, some with a distinct stratification of the fluorophore. The deuto and tritocerebrum and the ventral nerve cord also contain monoaminergic neurons. Of the brightly fluorescent areas in the whole of Crustacea, only the central body consistently exists in all species. The other areas of concentrated fluorescent neuropile are restricted to smaller taxonomic units and differ from each other. p The monoaminergic neurons in Crustacea are sensory, motor, and internuncial, and also belong to a fourth type which mimics the neurosecretory neurons in neurohaemal organs. Only one example of a monoaminergic sensory neuron is known (in Anemia, a non-malacostracan, Aramant and Elofsson 1976), a few motor and a few neurosecretory mimics (the latter in malacostracans). Most are internuncials.
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| 3. |
- Axelsson, S, et al.
(författare)
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In vitro-uptake of L-Dopa and catecholamines into the epidermal Langerhans cell
- 1978
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Ingår i: Acta dermato-venereologica. Supplementum. - 0365-8341. ; 79, s. 31-35
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Tidskriftsartikel (refereegranskat)abstract
- The Langerhans cells are capable of taking up L-dopa and the catecholamines dopamine and noradrenaline when exposed to these substances in vitro. Within the cell L-dopa is found in the cytoplasm as well as in the nucleus, whereas the catecholamines are confined to cytoplasmic granules. The L-dopa uptake is most probably carrier-mediated and the hypothesis is brought forward that L-dopa enters the cell by exchange diffusion. At present little is known about the nature of the amine uptake mechanism.
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| 4. |
- Elofsson, Rolf, et al.
(författare)
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A catecholaminergic neuron connecting the first two optic neuropiles (lamina ganglionaris and medulla externa) of the crayfish Pacifastacus leniusculus
- 1977
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Ingår i: Cell and Tissue Research. - 1432-0878. ; 182, s. 287-297
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Tidskriftsartikel (refereegranskat)abstract
- The crustacean optic neuropiles, the lamina ganglionaris and especially the medulla externa, show a specific pattern of green fluorescence with the fluorescence histochemical method of Falck-Hillarp. Normally, only the terminals and the cell bodies fluoresce, but in reserpine-treated animals exogenous catecholamines are taken up by the whole adrenergic neuron and are thus visualized as a whole. Incubating crayfish optic neuropiles in dopamine or α-methylnoradrenaline after reserpine treatment demonstrated a tangential neuron connecting the lamina and the medulla externa. The morphology of this tangential neuron differs from the two types of tangential neurons, Tan1 and Tan2, previously characterized with Golgi techniques. The catecholaminergic neuron thus constitutes a third tangential neuron type.
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| 5. |
- Elofsson, Rolf, et al.
(författare)
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A layered rhabdom in an isopod (Crustacea). A case of convergent development.
- 1977
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Ingår i: Zietschrift für mikroskopische anatomische Forschung. ; 91, s. 415-420
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Tidskriftsartikel (refereegranskat)abstract
- The isopod species Astacilla longicornis (Sowerby) has a layered rhabdom, which is the first case reported in isopod crustaceans. The rhabdom comprises the rhabdomeres of six retinular cells. It is surrounded by an extracellular palisade. Usually, palisades are intracellular in arthropods. A layered rhabdom is found in taxonomically widely separated groups within the Arthropoda and no intermediate forms are found between the different, highly specialized rhabdom types present. It is concluded that the layered rhabdom represents an example of convergent development.
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| 6. |
- Elofsson, Rolf
(författare)
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A peculiar kind of pigment cell in the compound eye of Lepisma saccharina L. (Thysanura)
- 1973
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Ingår i: Entomologica Scandinavica. Supplementum. - 0105-3574. ; 4, s. 87-90
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Tidskriftsartikel (refereegranskat)abstract
- The ultrastructure of the primary pigment cells of the compound eye of Lepisma saccharina is described. The cells are four in number. The pigment granules are contained in fingerlike protrusions from the pigment cells. These protrusions project into the enlarged basal lamina surrounding the ommatidial top. The large basal lamina could have given the impression of a cell (called corneagen) in the light microscope.
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| 7. |
- Elofsson, Rolf
(författare)
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A presumed new photoreceptor in copepod crustaceans.
- 1970
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Ingår i: Zeitschrift für Zellforschung und mikroskopische Anatomie. ; 109:3, s. 316-326
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Tidskriftsartikel (refereegranskat)abstract
- A new photoreceptor in the Copepoda is described. The organ, previously called Gicklhorn's organ (Elofsson, 1966a), is paired and is usually situated beneath the cuticle of the front. Each member of the pair consists of two cells. From the anterolateral position, two nerves lead to the lateral part of the brain. No connexion with the nauplius eye is found. Each cell of the organ has microvilli, two nuclei, dictyosomes, and large cisternae of the endoplasmic reticulum. Except for the binucleated condition, the cells closely resemble the retinula cells of the copepod nauplius eye.It is concluded that, because of its independent position, the new photoreceptor is not a detached part of the nauplius eye. As there are no accessory structures present and no missing links so far known, it is doubtful whether it can be regarded as a vestigial compound eye. The most plausible hypothesis is that the new presumed photoreceptor is an independent structure without connexions either with crustacean compound or nauplius eyes.If the function of the nauplius eye is considered by itself the improvement contributed by the new organ is probably modest because of its low level of organization. Some experimental evidence on light reception in Copepods points to a possible function in response to directed light.
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| 8. |
- Elofsson, Rolf
(författare)
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Brain and eyes of Zygentoma (Thysanura)
- 1970
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Ingår i: Entomologica Scandinavica. Supplementum. - 0105-3574. ; 1, s. 1-20
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Tidskriftsartikel (refereegranskat)abstract
- The brain, the compound eyes and the ocelli are described for some zygentomid species. Special interest has been focused on Tricholepidion gertschii, a newly discovered, primitive species. The brain morphology shows great similarities in the general shape and in details within the whole suborder. The compound eyes of Tricholepidion gertschii and Lepisma saccharina resemble each other closely. The present investigation has shown that the zygentomid and pterygote compound eyes are similar in that there are no corneagen cells. The view that the compound eyes of the Zygentoma should constitute a connecting link between crustacean and insect compound eyes can no longer be maintained. Tricholepidion gertschii possesses three ocelli. Their structure stresses the connection between thysanurans and pterygote insects. In this connexion the homology of reduced ocelli is discussed and their nerve contacts reinvestigated.
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| 9. |
- Elofsson, Rolf, et al.
(författare)
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Catcholaminergic salivary glands in Gammarus pulex (Crustacea, Amphipoda): An electron microscopic and microspectrofluorometric study
- 1978
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Ingår i: Journal of Ultrastructure Research. - 0022-5320. ; 64, s. 14-22
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Tidskriftsartikel (refereegranskat)abstract
- The type of gland (salivary gland) described here for the amphipod Gammarus pulex belongs to the tegumental glands, which have different structural characteristics. The present type, called rosette gland, is common in some crustaceans and is located in the ventral half of the head. The functional unit is a lobule of gland cells with a central-draining duct. Ducts from groups of lobules conjoin and terminate on the body surface at different points around and in the mouth and mouth parts. With the fluorescence histochemical method of Falck and Hillarp, specific green fluorescence was discerned centrally in the lobules and was confined to the gland cells. The spectral characteristics of the fluorescence, as revealed by microspectrofluorometric analysis, indicated either a mixture of dopamine and a presumed new catechol compound or the presence of two tautomeric forms either of dopamine or of a new catechol compound. Evidence of new catechol compounds with similar spectral characteristics has previously been found in the sensory cells of some invertebrates. The fluorescence distribution within the lobule coincides with the presence, ultrastructurally, of large dense vesicles in the gland cells. These dense vesicles occur in the predominant cell type, also characterized by a smooth endoplasmic reticulum. The other cell type in the lobules differs ultrastructurally by possessing a rough endoplasmic reticulum and a different vesicle type. No innervation of the salivary gland was perceived.
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| 10. |
- Elofsson, Rolf, et al.
(författare)
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Catecholaminergic innervation of muscles in the hindgut of crustaceans
- 1978
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Ingår i: Cell and Tissue Research. - 1432-0878. ; 189, s. 257-266
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Tidskriftsartikel (refereegranskat)abstract
- The crustacean species Pacifastacus leniusculus and Gammarus pulex were investigated by electron microscopy in a search for possible neuromuscular junctions in the hindgut, which has a rich supply of catecholaminergic fibres. True neuromuscular synapses were found in both species between nerve terminals containing dense-core vesicles (80–110 nm in diam.) and muscle fibres. We suggest that the dense-core vesicle terminals contain a catecholamine, and this is supported by ultrahistochemical tests for monoamines. Two types of junctions are found: one in which the nerve terminal is embedded in the muscle cell (both species) and one in which protrusions from the muscle cell meet nerve terminals (Pacifastacus). Gammarus pulex, which has only circular muscles in the hindgut, has only catecholaminergic innervation, whereas Pacifastacus leniusculus has circular and longitudinal muscles both with at least two types of innervation.
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